Trying not to think about it is very hard. The basic problem can be demonstrated with the old challenge:

Try to not think about a pig dancing.

It's hard to ever truthfully claim that you've now achieved the state of not thinking about a pig dancing because the very process of checking to see if you are indeed thinking about a pig dancing conjours up the image of a pig, dancing.

Equally, if you're desperate to not think about it, as in the instance of trying not to think about it, you usually feel the need to constantly check to see if you're thinking about it yet, or to work out how long you've been not thinking about it for, and both of these end in you thinking about it, God damn.

Thinking about it, God damn is absolutely fatal to trying not to think about it - you realise you're obsessed with it, and it keeps coming up, and you become even more desperate to not think about it, and try harder not to think about it, and check to see if you're thinking about it yet more often, and feel more pleased with short periods of not thinking about it and very quickly the whole thing spirals horribly out of control and you're not only thinking about it, God damn near-constantly, but you're starting to oh God, still fucking think about it.

The secret to not thinking about it is, in essence, ice-cream vans, or in a purer, more difficult to achieve form, ice-cream in isolation. The masochistic circle of thought detailed above is so incestuously self-referential that it needs very strong external stimulus to break it, and in our smallish, roughly every day lives, the most practical instance of this is oh, hey, ice-cream.

Dancing pig image by Clone.