(BYE-frend-lee) A person that seems to switch between liking and being nice to you and hating you. Almost like bipolar, except with their interactions towards certain people. This person is either a friend or a jerk, and they alternate with each personality a lot. If you really can't decide which one, then the person is a jerk and they don't deserve to be your friend. Bifriendly people are best avoided.
(name): hey, did you see my new youtube video?
MS: yeah, it was awesome
NEXT DAY (or less than one day)
(name): I discovered this new death metal band that's amazing
MS: stop talking to me! You're so annoying
(name): why the fuck are you so bifriendly?