During the scenes where Hank spends the night to keep an eye on Bill, the background music resembles the theme from The Odd Couple.
Hank mispronounces "vacation" yet again in this episode.
The first mention of Buckley's Angel in the series.
The only part of the script that writer Paul Lieberstein wasn't happy with in the end involved Lenore (the real ex-wife of Bill, not his iguana or what Bill's insanely pretended he'd become) in the 3rd act. He felt that the scene where Lenore called to say she wouldn't attend the Hills' holiday party, nor speak to Bill or even send him any phony best wishes, felt too much like Lenore was watching the party somehow and taking pains to be as cruel to Bill as possible. But they kept it in because no one came up with a better way to both get Bill to completely fall apart and then to confront Hank (co-splaying as Lenore) with his anger so he can start his journey back to normalcy. Lieberstein earned an Emmy nomination for Best Comedy Script anyway, though he didn't win.
This episode is supposed to take place in December, yet all of the trees have green leaves.