Occasionally I lift with my pal Kevin, but that's really only if I need a ride to the gym. He's not much for motivation, given that he doesn't get any Pre or PWO nutrition, doesn't eat like he should, and as a result, he's been benching the same weight since March. I keep asking him about it, to absolutely no effect.

I mainly relate that story to say - I find lifting with a partner mostly just distracting. If you really want to get stronger, the motivation has to come from yourself - and if that's so, I like lifting alone so I can focus my thoughts.