I am stuck on this level.

But not frustratingly stuck, no. Happily stuck. I try different things – in this case I was trying a few high level towers, rather than lots of cheaper ones – and I enjoy myself. I don’t get annoyed with the game or myself, I just shrug and try again. Over and over and over again. I’ll beat it one day, then it’ll be on to the next. I hope I get stuck on that level for a while, too.