Human beings are exceptionally fond of immunity - we admire it in our bodies, anyway. We take vitamins, and we go for walks. We drink healthy green liquids and buy organic. We do all sorts of things in the hope that when a virus comes along, our immune systems will mobilise and get rid of the evil so-and-so.

So far, so sensible!

But there is another sort of illness that keeps knocking people flat. A careless remark from a stranger. A rejection. An unanswered message. A criticism from a boss who hasn't slept properly in three days. These things are not supposed to be life-threatening, and yet they can ruin a perfectly good week, or sometimes a perfectly good year.

Curiously, we do not talk much about immunity where these issues are concerned. When it comes to emotional pain, most of us believe that it is simply a part of life. If we get a lot of it, then life must be cruel - but we have to plough on, regardless. So when we get hurt, we develop elaborate ways of dealing with our emotional pain.

We analyse ourselves. We analyse our parents. We analyse our childhoods. We analyse the fact that we are analysing our childhoods. Some people repeat affirmations in front of the mirror while brushing their teeth. Some meditate and become convinced they have transcended the problem altogether. Some read books. Some read many books about other books that they believe they should read. Some get very good at explaining why they feel the way they feel - because they read about it all in those books.

And this can be particularly useful. Understanding things is nice; it makes us feel clever, even wise. However, the trouble begins when understanding changes absolutely nothing - and this happens more often than we wish it did.

A person can explain in great detail why criticism bothers them and still be devastated by that criticism. Another person can know they deserve better and still walk straight into the same disastrous relationship, only with a new partner. Yet another poor soul can swear never to repeat an old mistake and then, with remarkable efficiency, keep doing the same thing over and over again.

It happens because knowing something and being changed by it are not necessarily the same thing. Most people know they should not hand over their self-worth to the moods and opinions of others, and yet they do.

A stranger says one unpleasant thing, and suddenly that stranger is in charge of the weather inside your head.

The question is not whether we understand our emotional patterns - because many of us do. The question is why those patterns continue to operate long after we have figured them out. Why does the reaction keep happening? Why does the same old machinery keep turning? Perhaps because understanding is only the beginning. Perhaps what we really need is something closer to immunity.

Not the absence of emotional pain. Not becoming cold. Not becoming indifferent. But the ability to encounter life's inevitable viruses—criticism, rejection, disappointment, uncertainty—without being infected by them every single time.

That would be useful. So, does such a thing as emotional immunity actually exist? And how does that work?

Now, the idea of emotional immunity may sound suspicious. We, humans, tend to become suspicious whenever somebody invents a new phrase. And quite right so, too.

After all, emotions are a part of being human. Nobody gets through life without disappointment, rejection, grief, embarrassment, jealousy, or the peculiar misery of sending a message and seeing that it has been read but left unanswered.

So, if emotional pain is unavoidable, then surely emotional immunity is impossible. Sounds like a reasonable conclusion, right?

The trouble is that most people hear the word immunity and imagine some sort of magical shield. No criticism and no rejection gets through. No unpleasant surprises. Nothing hurts, and there is no pain. What a blissful arrangement!  Unfortunately, it would also require us to stop being human.

So, no, that is not what I mean at all.

A healthy immune system does not prevent germs from entering the body. The germs do get in. The immune system simply refuses to let them set up permanent residence. Life works much in the same way. People will still criticise you. Relationships will still end. Plans will still collapse at the last minute. You will still make mistakes. You will still encounter disappointment. The universe has shown no signs of cancelling any of these services.

The difference is what happens next.

For some people, a criticism remains a criticism. For others, it becomes evidence that they are fundamentally defective. A rejection remains a rejection - or it becomes proof that they are unlovable. A setback remains a setback. Or it becomes confirmation that success was never meant for them in the first place! The event arrives as a visitor, but then it steals the furniture, changes the locks, and starts collecting rent. While quietly poisoning you at the same time.

This is where emotional immunity becomes interesting.

Not because it prevents pain, but because it prevents pain from becoming a permanent resident. The criticism is heard and the rejection is still felt. The disappointment is acknowledged. But none of them are allowed to seize control of your life. The event remains the same, yet it is not promoted to the position of your life philosophy.

This raises an interesting question. If criticism, rejection, disappointment and uncertainty are the emotional equivalents of viruses, why do they infect some people far more thoroughly than others?

Take two people. Both receive exactly the same criticism. The first person thinks, "Well, that was unpleasant.", and then they make a cup of tea and get on with their day. The second person spends the next week replaying the conversation in their head. By Thursday, they have concluded that they are incompetent. By Friday, they are considering a new career. By Saturday, they are wondering whether they should have been born at all. Same criticism. Different infection.

Or take rejection. One person feels disappointed and moves on, while the other feels as though somebody has reached into their chest and ripped their heart out. Same rejection. Different infection.

This is awkward because most of us go through life believing that events and other people cause our suffering. Criticism hurts because criticism is painful. Rejection hurts because rejection is painful. Simple? Except it isn't.

If events alone caused suffering, then everyone would react to the same event in exactly the same way, but they do not. Human beings can barely agree on what to have for lunch, never mind how to respond to disappointment, so something else must be going on.

Perhaps criticism, rejection and disappointment are not the illness at all. Perhaps they are merely the virus. And perhaps the severity of the infection depends less on the virus itself and more on the environment it encounters when it arrives. Now there is an uncomfortable thought, because it means that the emotional pain we experience may not be determined entirely by what happens to us. It may also be influenced by what happens inside us afterwards.

A criticism enters the system. A rejection enters the system. A disappointment enters the system. Then something peculiar happens. One person's mind says, "Thank you for your contribution, you can go now", while another person's mind says, "Excellent. Let us use this as evidence for every terrible thing we have ever suspected about ourselves." The virus arrives. The real trouble begins when it finds somewhere comfortable to live and fester.

This is perhaps where emotional immunity parts company with its more famous cousin: emotional intelligence. Emotional intelligence has done very well for itself! Books have been written about it. Courses have been sold. Consultants have built entire careers around it. It has become one of those phrases that intelligent people enjoy mentioning to other intelligent people. And quite right, too.

There is nothing wrong with emotional intelligence. Far from it. If somebody asks you how you are feeling and your answer is "fine", while you are actually dying inside from anxiety, resentment, irritation, self-doubt and a vague sense that civilisation may be collapsing, then a little emotional intelligence could be enormously helpful. It is useful to know what is going on inside your own head. Many people do not.

Emotional intelligence helps us recognise what we are feeling, and it helps us understand why we are feeling it. It helps us identify patterns in ourselves and in those around us. These are admirable accomplishments. The trouble is that understanding a virus and being immune to it are not the same thing.

A person may know exactly why criticism affects them. They may know where the pattern comes from. They may know which parent, teacher, former partner or unfortunate childhood incident first planted the seed. They may be able to explain it beautifully. Some can even explain it in song form.

And yet the criticism still hurts. The rejection still hurts. The spiral still begins.

A person can become extraordinarily intelligent about their emotions while continuing to be pushed around by them. This happens more often than one might expect.

Imagine somebody standing in the rain. They understand rain perfectly. They know where it comes from. They understand the formation of clouds. They could probably give a lecture on atmospheric conditions. Meanwhile, they are still soaking wet. Knowledge of rain and protection from rain are not necessarily the same thing.

Likewise, emotional intelligence can tell you what is happening. Emotional immunity determines what happens next. One helps you recognise the storm, while the other stops you from being carried away by it.

Ideally, of course, one would like both. Emotional intelligence may explain why you are standing in the rain. Emotional immunity is what stops you from catching pneumonia.

Whether emotional immunity can be developed is a question for another day. For now, it is enough to observe that understanding our emotions and being protected from them are not quite the same thing. One helps us explain the storm. The other helps us survive it. And in a world where many people are remarkably intelligent about their suffering, that distinction may be worth paying attention to.