In my anecdotal experience, the guy who did work related stuff in his spare time was an absolute nightmare to work with (but he was friends with the boss so saf

In my anecdotal experience, the guy who did work related stuff in his spare time was an absolute nightmare to work with (but he was friends with the boss so safe to do whatever he liked). He seemed to think he was a lot better developer than what he actually was. He churned out a lot of small projects, but they never seemed of great quality and the question of "why?" came up a lot of the time (he developed an OCR reader to process student evaluation forms, rather than an online form). My other colleague who did tech related (but not work related) stuff in his spare time was knowledgable about a lot of stuff and a lot more pleasant to work with. He knew a lot of security related stuff that came in relevant when we thought we had been hacked.