How do you deal with it?
It's for all sorts of things. Let's say I need to do the school run at half 7, and I'm ready to go at 7. For those 30 minutes waiting, I can only do things that I know will definitely take less than 30 minutes. E.g. do piano scales. Or put a specific thing away.
E.g. I can't put away laundry because it might take longer than 30 mins to do it all. I can't start a draft of an email I need to send later that day.
I don't know why it is like this.