Perhaps a slightly less common reason: I felt I was underappreciated. At my old place, I was often the only person fighting fires, fixing critical bugs, and wo

Perhaps a slightly less common reason: I felt I was underappreciated. At my old place, I was often the only person fighting fires, fixing critical bugs, and working on critical "we want this yesterdat" requirements (think new Government rules that require significant changes from our side). It wasn't a big company so I didn't mind that I was alone, but it did suck that I saw people who worked on shiny new features got much more appreciation than I did for keeping the lights on.