Continuity mistake: As Daria and Jane are talking to each other in front of the lockers in the hallway at school, the locker to the right of where Daria is standing is locker #307, then shows it as #104, then #307 again.
Factual error: When people are dancing around the car that Daria and Tom are sitting in, the crescent moon is shown in the night sky in the background over the horizon, with the crescent facing upwards away from the horizon. This would be impossible as the crescent can only face down into the horizon at night (never away from it).
Answer: "Mack Daddy" was a 90s phrase meaning "Ladies man," and Mack simply doesn't like the stupid nickname.
Brian Katcher