I encourage you to write about troublesome things. That doesn't mean you can't write about love and laughter, but you should also realize that all good stories about relationships are about the problems in relationships, and that all humor comes from pain and suffering. Respect your characters. Stories are about people, not about symbols. You and your reader must spend time with these characters, so make them individual and interesting.
Dialogue has to sound like real people talking.
They may be outrageous people, and they may say outrageous things, but only the dullest people speak in cliches, and the dullest people are seldom worth writing or reading about. Another thing that real people don't do is pack their conversations full of plot information. Read your words aloud. Be prepared to be embarrassed, and if you're embarrassed because something sounds phony, you have some rewriting to do. All writers rewrite.