My wife and I go to the gym together, but we don't always train together. Every now and then I will go help her. Mostly we do things solo now.
I find that it sucks to train with people; switching plates out and what not. I've yet to train with a friend that lifts on my level and trains the way I do. When I was reliable myself, I often found that my "training buddy" wasn't, and that caused further frustration.
Unless I'm shooting for 1RM PRs then I rarely require a spot. This doesn't mean that I don't make progress or rep PRs frequently, because I do. If I don't have a spotter, I push significantly harder to make the lift. It gives me that motivation because I know that if I don't complete the lift, due to lack of strength, then I'm ****ed.
I've missed lifts with spotters that I've made without spotters - its all a mental game to me. And I've yet to miss a lift like this, which is why I'm able to type this for you now.
I guess you can say that I like to live on the edge.