Dani: Yup, theres more than be nice, and be tolerant (those are different.) The third corner is "Figure it out for yourself, and have the courage of your own convictions". There's more to your faith, of course, but I really think that's the essential common ground UU's tread on. Truth is of course, not all even are nice!
MudJack, you may be a UU Christian without knowing it! (Just kidding, I always thought that was a dumb slogan --you get a choice. I don't identify myself as a UU anymore, although it was a significant part of my heritage and personal development.)
As for the burning question mark, the old joke is that given a choice between going to heaven or going to a discussion group on what is heaven?, a UU is someone who would choose the discussion. They are kind of notorious for intellectualizing everything.
Best regards
Bill