Lister is such a maniacal and disgusting character that it is almost comical (key word : almost).
He gets angry at the sorcerer that cannot cure Sylhan's limp, when he is the cause of said limp to begin with. Then he attempts force feeding him and gets angry yet again when the cup eventually falls. He is such a compelling representation of abusive people that you may find in every day life, I truly wonder why Lister would treat his supposed childhood "friend" so badly...