I've no earthly reason to think I can trust you, and, if I do this and get away with it, you'll have something on me that you can use whenever you want to. Since I've got something on you, I couldn't be sure that you wouldn't put a hole in me some day. All those are on one side. Maybe some of them are unimportant - I won't argue about that - but look at the number of them. And what have we got on the other side? All we've got is that maybe you love me and maybe I love you.