I could never be a tech on a payroll, because if I am called to fix one problem, I end up "seeing" things I don't like, and there goes the afternoon  ;D

That's something I battle with also. I learnt years ago to only repair the problems, and not go to deep when at a customer's house. It can end up either being costly for the customer, or you spend way to much time and end up loosing money yourself.