rant on parenting a teenager

Extract from a recent discussion with my 13yr old, she was speaking about her friend, whose parents are separate:

kid: poor my friend, she must spend the weekend with her father
dad (me): what's wrong with her dad?
kid: oh, he's a very bad guy
dad: really? How bad??
kid: let me just tell you: if you were to meet him you would immediately say he's a very good person