A Paladin, a barbarian, and an abjurer, all fifth level, find a genie's lamp. They rub it, and a genie comes out, laughs and says "for freeing me I shall grant you each one wish".
The paladin wishes for the means to end all war, but before the Genie could grant the wish the abjurer counterspells with dispel magic.
The barbarian steps up, and wishes for a thousand goblins to punch to death, which the abjurer counterspells again.
When the barbarian asks what did he do that for, the abjurer curses and shouts "I wish you two numbskulls could tell an efreet from a djinn when you see one!"