My coworker is always stealing my ideas and then acts like they are his while at the same time being two-faced enough to pretend he is my friend. Advice?
Uh oh, somebody's Mom didn't teach them how to play nice in the sandbox. What really gets on my last nerve is how often this type of co-worker seems to come out smelling like a rose while you are standing there wondering "hey, what happened?"
Lesson #1 - except in very rare cases, these people DO know exactly what they are doing. They are basically spotlight stealers who don't have any original ideas of their own. The first time this sort of behavior rears its ugly head, you have to go back to the person and let them know that you're on to them...and so is everyone else. The next time, you have to keep your ideas to yourself.
And Lesson #2 - branch out and find some other friends...this so-called "friendship" is going nowhere fast.