I like it when you're talking to someone. And you're agreeing with each other about something that people don't often agree on. So you've found someone with the same unusual sorts of ideas that you happen to have. And so you talk. And then they say something which suddenly seems strange. And you're not sure if you've just misunderstood what they just said, or if you've misunderstood all the stuff they'd said before it. You're trying to work it out, and trying to think of a polite way of checking which it is.
And then they say "But of course, that's not really true...", or they suddenly laugh at you wryly. Or the conversations twists back around into the direction it was heading, and the kink it had just been on makes sense. And you realise that you still agree on the odd sort of thing you're talking about.
Not only do you understand them when they are making sense, but you understand them when they aren't. And vice versa. That is something I love.