Fixating on things that don’t matter
An idle mind is a dangerous thing. When you don’t have bigger picture things to focus on like the direction of your career or a social life or hobbies, your mind needs something to fixate on. So it can start to fixate on things like…the fact that your partner bought regular sharp cheddar cheese instead of extra sharp cheddar when you explicitly asked for the extra sharp. Okay, no need to blow up the whole day over it.