Love Is in the Air (a.k.a. What I Did for Love) - S1-E14
Continuity mistake: When Susan's reading her Valentine's card, in the shot over her shoulder she closes it. The angle then changes so we can see one of the other housewives approaching - her card's now open and she shuts it again.
Chosen answer: Hardly any. As Joss Whedon had to fight fairly hard just to get a season five at all, he was aware from the start that cancellation was quite possible. As such, he designed the season as if it was the last one, but with the possibility of using it for a launchpad for a season six, should they have been given one. The only likely alteration was that, had they received a sixth season, the death of a major character in the final episode would probably not have occurred, or at least his fate would have been left ambiguous, to allow the character to return.
Tailkinker ★