My worst work block is thinking I have to rush while working. I greatly dislike rushing, I like to do things calmly. So when I started to be told that as an academic, you had to always do everything as quickly as you possibly could and as superficially–or you would be cut–I decided I preferred not to be an academic, and would prefer to return to the assembly line.
I cannot face starting anything if I think I have to rush myself through it or take it at a breakneck pace. As soon as I remember I do not have to rush like that, I start perfectly well.