Continuity mistake: In "Getting Married Today," Gabby's hair in the beginning has her bun high on her head and her tiara is visible from the front. When Bree walks in, and when she overhears Victor and his father talking, her tiara is farther back on her head and no longer visible from the front.
Continuity mistake: Throughout the series, any time you see into the front door of the Scavo house (from an exterior shot), there is a blue wall with a table in front of it, however, interior shots show that the front door leads to the lounge, with the staircase opposite the door.
Continuity mistake: Season 2, Episode 23: "Remember, Part 1" - In the 1994 flashback where Bree introduces herself to Mary Alice and forces her son Andrew to apologise when he stole a ornamental garden frog, the position of the frog changes between shots as Bree hands it to Mary Alice.
Factual error: When Gabrielle becomes a widow she marries Carlos again in front of a priest. But the Catholic Church doesn't admit divorce, so in their eyes Gabrielle and Carlos were still married. They should have repeated a civil wedding, since only the civil effects of marriage were ended with their divorce.