There's only one reason why a character drinks: to seek confrontation. To fight for what they want in ways normally denied them.
Michael ShurtleffAn actor must make his needs (goals, wants, objectives) so strong that he is willing to interfere with the other actor in order to get what he needs. Interfering means getting in their way so that what you want is stronger than what they want.
Michael ShurtleffAn expression of feeling isn't worth anything unless it interferes with what the other actor in the scene wants.
Michael Shurtleff