A random childhood memory of mine is of being about 10, and wondering what my life would look like when I was grown up and didn't live with my parents1 any more.
At that age, a thing I was enjoying doing in my spare time was making cardboard models of polyhedra. And I remember having the thought that once I was a grown-up, perhaps I might still feel moved from time to time to sit at home cutting and folding and gluing cardboard, but since I wouldn't be living with family any more, there'd be nobody else to show the things to once I'd made them. I found that thought rather upsetting, and started to think that perhaps being an adult wouldn't be very nice; I had an image of myself spending my life sitting in a house on my own, with nobody to talk to, and even the ways I was accustomed to amusing myself on my own not being as much fun as they used to be.
It was only a passing thought; there were clearly lots of things wrong with it, several of which I spotted fairly soon, so it didn't continue to worry me for very long. But it stuck in my head well enough that even now I can clearly remember having been worried about it once.
During the weekend just past, I put a fair amount of effort into helping drswirly design and make a cardboard cube with group theory notation all over its faces, for maths-teaching purposes. There were enjoyable coding challenges involved in writing the program that put all the right notation in the right places and printed out the net; when it was finished, we looked at it and went ‘ooh!’ (because it's quite pretty), and it will also come in actually useful to him and possibly to other maths-type people. And then he rewarded me with cake.
At times like this, I feel an urge to travel back in time and reassure my 10-year-old self that he was wrong in the one part that mattered. I would tell him, it turns out you're right that you'll live on your own when you grow up, and it turns out you're also right that you'll still make polyhedra every so often, but notwithstanding your pessimistic analysis it will still be great fun.
1. (Hmmm, I nearly wrote ‘didn't live at home any more’ there, which made sense in my head but once written down it's clearly a contradiction in terms!)