An argument between Leonard and Penny proves "inconvenient" to Sheldon. We learn that Sheldon's parents argued a lot when he was growing up, and he doesn't like to hear people arguing at all. Penny had invited an old friend (a male guitarist) to stay at her place and Leonard was quite upset about it. Everyone else was arguing, too: Raj and Howard, Raj and his parents, and Howard and his mother. Sheldon even went to the Cheesecake Factory by himself to try to talk Penny into apologizing to Leonard so he could get on with his life. At the end of the show, Penny's friend is seen sleeping on Sheldon's couch as Leonard and Penny are in bed together in her apartment.
The title refers to Penny's friend's occupation as a guitarist.
