It's amazing the stuff past employers don't care about. As an example, I was with a large point of sale terminal company from when they were small. After a few years with them, I did a prank involving some of their equipment. I think I kinda wanted to be fired, frankly. So, I was fired, got a nice severence package and some paid free time, etc. Years later I have my own company and need some repair parts for some of their terminals. Lo and behold, they remember me all right, in glowing terms! I ended up having an account with them to order parts with.