I once saw a popular wedding band rehearse. There were two guitarists: one handled all of the lead playing and the other played a solid rhythm while also acting as their lead singer on several songs. During a short break, the lead guitarist wanted to jam on some bebop and asked the rhythm player to give him something to play off of. The rhythm player said, "I'm not that guy. If you ask me to play some Van Halen or some other rock stuff, I'll rip your face off with that kind of playing. But I'm not that super versatile, can play any style at the drop of a hat, guy."
The rhythm player happens to be a friend of mine and he is a truly fantastic rock guitarist, but in a room full of super versatile, can play any style at the drop of a hat guys, he might be considered a hack. I'm just like he is. I can play the hell out of the music that I enjoy playing, but in a room full of "real" musicians, I might be considered a hack.