David was in the wrong about Stacy

The episode where that hot blonde girl is working at the diner and David is trying to get a date with her, we're made to think Mark is the asshole in that situation. Like Mark can't stand it if David might appear equal to him or something.

But remember it was David who was taunting Mark about Stacy, Mark was ignoring her before then, she was coming on to him like crazy and Mark ignored her. Yet David ran up to him going "hey what are you doing you're a married man" and Mark even said "I'm not coming on to her shes coming on to me" which she clearly was. David couldn't stand it that she was more interested in Mark than him.

Then David asks her to model for him so he can paint her, she agrees, then David proceeds to go over to Mark and taunt him about it and calling him dumb "Gee Mark i bet you wished you used those crayons for more than just stabbing people now huh?". So then Mark gets pissed and screws him over by offering to fix her car so she can't go to the concert with him.

Mark wasn't totally right by doing what he did but David did kinda ask for it, Mark was content with ignoring Stacy until David began taunting him about getting a date with her.