Sunday rides, I like to do alone (I can't imagine ever riding in a group, but have quite enjoyed riding with one or two people I know well).
It's the whole gubbins of the group ride that puts me off, the rules, the fact that you need to know the rules, and so forth. Nothing against those who like them, but I'm not sure I can be bothered with the faff.
touring's better with someone else, I think, not least so that that person can say "Are you sure this is the right way[1]?" and "Isn't it time we stopped for a drink[2]?"
[1] I have almost certainly taken the wrong turning, let's have a look at the map.
[2] By golly, you're right. Fancy a cake as well?