get on the bad side of (someone)

get on the bad side of (someone)

To be or become displeasing to someone; to do something that provokes someone's anger, contempt, or dismissal. Be sure not to get on the bad side of the superintendent— she's a powerful woman in the school district. I'm afraid I may have gotten on the bad side of your friend with my off-color remarks.
See also: bad, get, of, on, side