I don't have a training partner, but Iam one of those guys who knows everyone at the gym, and am part of the social scene, get invited out places. But it's a very select crowd ,we are all serious trainers and only have quick chats during rests, or when setting equipment up.It's nice like that, as I have noticed in other gyms I used to go to, people never talk to each other so you end up in situations where people are on hogging squat racks or whatever. Because we are all friends,we know each others routine, so we make sure a certain piece of equipment is free for someone and even strip the weights off if needs be.
I personally think training partners are an inconvenience, especially if you are a very tall dude like me and try training with someone who's say 5ft 9 . or you are someone who trains a certain way, some people get much out of short rests others take a 5 min break.who cares right if you grow and get stronger,but certain training people respond to it different. I myself do extremely high volume with short rest periods lighter weight than average and focus on form and doing negatives , 70's style bodybuilding training, no one else in my gym trains like that. I also know someone who was training for a bodybuilding contest and trained with a guy who had competed in the past, and the guy who had competed in the past was a beast, a real beast one of those guys who could leave the gym for 6 months come back and bench and squat massive numbers and the guy training for his first contest got injured trying to keep up with him.