be laughing on the other side of face

be laughing on the other side of your face (British, American & Australian, informal, American & Australian, informal)

if you say someone who is happy will be laughing on the other side of their face, you are angry about the thing that is making them happy and think that something will soon happen to upset them. You'll be laughing out of the other side of your face if you fail your exams.

See also: face, laugh, other, side