I think it helps to have a core genre of music that you play. It helps when people say to their friends "I saw this ace <insert genre> band last night". However, I do enjoy surprising people with a few choices - have observed raised eyebrows (but in a good way) and comments sometimes passed like "Oh cool, you do that song". We try and tread that line. There'll be grumpy punters if we don't play any AC/DC, but they don't mind if we throw in the odd curve ball.
Weddings can do one - there's a reason the money's good - far too much pressure, far too much having to learn one-off pap songs that you hate, venues can be Richards about noise levels and arranging access - no thank you, I do this for fun. I've only ever played one wedding, and it was with my originals band because it was a mate who really likes us and specifically requested us - we did all our songs to date and padded the night out with covers that we enjoyed playing, it was a good night.