You know, your comment really hit me for some reason. I'm working at a place now where the boss is really quite rude to some of the junior devs. It's gotten to the point they are afraid to ask questions for fear of his response. As a senior I see this and make an effort to talk and sympathize with the junior guys but feel powerless to stop my boss acting this way - he is very defensive and argumentative whenever I bring this stuff up.

So your comment about watching people being treated a certain way really hit home. Perhaps it's time for a more frank (and private) discussion with my boss, or even a new job.

Get a good job offer first. It'll be him asking you why you consider leaving. If the talk goes bad he suffers his own inflicted wound and perhaps will learn a lesson, while you land on your feet.