I always think of things when I'm high that sound to me like absolutely revolutionary insights at the time, but are just trivial or silly when I am sober again.
I also often have moments when I become very anxious that I'm dying or something, and then forget about it like 10 seconds later.
It would be a lot more fun for me to be high on weed if I didn't have a pseudo panic attack every few minutes because I'm thinking I'm about to either have a heart attack or throw up lol