Don't pretend, that's all you've got to do. Most people are bad people, but that doesn't mean they have to be a bad bad person. Don't even pretend to be a good person, never confess what crimes you've done (if you have any) but don't pretend like you haven't done something. Don't pretend like you genuinely like people either, if you think someone is rude or lame don't become friends with them and don't make them feel worse in the end.