Some things are bad. Some are terrible. Some are downright evil. Some people are cruel. Some beastly. Others downright evil. Of these and so many other manifestations of both the awful and the icky, I say: 'Well, so it goes.'

But disappointment, disappointment is a monster of a whole other dimension. We generally understand good and bad, up and down, pyjamas and business suits. These are (in theory or reality) palpable opposites.

Disappointment both does and does not traffic in opposites.

There is a thing you want. You do not get that thing. You are disappointed because of not-thing. It's not really an opposite, is it? It's more like nothing - an empty space, something that fell through your fingers.

If you were hoping for a promotion and didn't get it, that's not opposite; the opposite would be a demotion.

Disappointment is easy to feel but often hard to describe.

What do we do with that? What do we do with this not-thing?

Most of us are so binary about everything. Are you a dog person or a cat person? Morning person or night person? Submissive or dominant?

This tendency to think in a polarised way seems counter-intuitive because most people are not one thing all the time. We are, usually, reasonably complicated and layered and contradictory. Like a trifle.

I think that's why disappointment wrecks us. It's not yes or no. It's just not. The difference between an expectation and the non-realisation of it is the trough of disappointment.

My own research on disappointment has been, to say the very least, brutally disappointing. I want to know why it hurts in such a piercing way. Why it has the power to undermine so much in us that is strong and resilient. After all, simply wanting something is no guarantee that you'll get it.

Expecting something, having something promised, working hard for it; none of these mean you will definitely get it. Why would you ever think it would?

I wanted explanations for how disappointment works, what it triggers. Instead I got a lot of how-to-cope-with-disappointment and how-to-reconsider-our-expectations.

When this column started, I thought I was mostly going to be writing about important and often misunderstood mental disorders. The real heavy stuff requiring lots of precise psychiatric and neurological perspectives and complicated scientific names with lots of Zs and Xs in them.

Instead, I seem to spend a lot of time talking about things that can lead to depression, cause anxiety, maybe push you to a psychotic breakdown.

No one is more surprised than I that I'm ok with that. Thinking about disappointment made me realise how ok with it I am.

Maybe it's because I suspect I'm on to something I'm even more interested in. Things like disappointment, secrecy, the state of friendships, the need to find ways to talk about our problems - these non-scientific-sounding things are the things that underpin so many mental health problems.

And disappointment may (I have no evidence, just a feeling) be one of the really big guns. Disappointment in ourselves, parents