Błędnie: Why are you making stupid mines when somebody tells you you're wrong? It's impolite. Poprawnie: Why are you making stupid faces when somebody tells you you're wrong? It's impolite.
"Mine" to 'mina' (taka, która wybucha, a nie wyraz twarzy). 'Mina' w tym drugim znaczeniu to "face", 'robić minę' to "make a face".