I have never ridden in groups other than a few times with one good friend back when he had a bike. I'm an introvert and tend to avoid groups of people like the plague, especially when I don't know most of the members. But I can relate to this "pick your riding partners carefully" idea in terms of bicycle touring. I once spent 9 weeks bicycle touring through Central America with a woman who drove me near insane before it was all over. I seriously think she had some mental issue. She'd "blow up" out of nowhere several times a day and then act as if nothing happened. This was over things like the speed at which I walked or drank water (too fast). I had met her a year earlier while solo touring the Pacific Coast and rode about 3 weeks with her and a couple of others, and did not see any of this behavior. I learned much later that she had been directing most of it to another guy in the group at times when I was not around to witness it.
It was the longest 9 weeks of my life, and a huge learning experience. I've done 5 or 6 tours since then, all solo with the exception of one with my girlfriend (who is awesome, but not really into bicycle touring). Going alone works great for me, whether it be on my motorcycle or bicycle. I love the freedom to start, stop, take breaks and decide the direction myself. There are no personality clashes and no disagreements over anything. And there is never any peer pressure to ride at a level I'm not comfortable with. I always take along some form of entertainment (book, laptop, whatever) and never get bored. And whenever I see a big group of bicyclists or motorcyclists on the road, I am always thankful I'm not riding in the midst of them. I imagine most of them are having a great time too, which is awesome. It's just not my thing.
