I was chatting with a new friend the other day & we were talking about coupledom; specifically about how often it is that you don’t like both halves of a couple you meet. He suggested that if you meet the couple as a couple, it’s more likely, but I wasn’t sure. At least in my experience, I tend to warm to one person more than the other, or just have more of a simpatico with one. The likeliness of liking both people in a couple goes significantly down when you’ve known one of the people for a while & then your friend introduces you to their new special friend.
That said, I can think of exceptions, of course, to everything I’ve just stated. In one case, we were so pleasantly surprised by liking a friend’s new partner & so enthusiastic about saying so that my friend of many years felt neglected as a result. (We reassured her, of course, that we loved her just as much.) In another case, I had a much easier friendship with a friend’s partner, & continued to be friends with him long after they broke up.
I assume there are always going to be people who like Betty more than they like me, and people who like me more than they like Betty. We appeal to different people because we do — I assume that’s also why we appeal to each other. (What those differences are I won’t bother to go into.)