In April 1996 at Asbury Park, NJ Greg made a point to acknowledge a request for 'Yesterday' from a very persistent fan. He offered to sing it by himself since they hadn't rehearsed it. After the first few a capella bars, Hetson joined in with Jay and Bobby following a beat later on the drums and bass. After fifteen seconds they all were committed and played it through, half-laughing because of the spontaneity of the whole thing.
Puffball contributed a faster and punker cover version to the album Fuck Hell -This is a Tribute to Bad Religion.
The song is called "Look Behind" in the Hate Yourself bootleg.