I prefer to work out alone so that I don't have to deal with someone else's routine, bitching, and lazienss. I haven't found anyone committed to excellence to work out with. I'm tired of working out with people who use poor form in order to lift more weight and then try to brag about it. I hate working out with people who get in there and then complain about doing "work" in the gym.
For the most part I use dumbells to avoid needing a spotter, but when I want to max on bench I convince someone to work out with me.