It might be pure lack of regard, but it might also be him trying to emulate what he sees in children's movies and TV shows. When the main character makes a plot-changing mistake or their fatal flaw comes to a climax, his or her circle of friends leaves them. That is, until the main character, driven by desperation and realizing the error of their ways, cries out to the heavens about how wrong they were and how much they regret what they did. Sometimes, the phrasing in the script can be as vague as "I WAS WRONG I'M SORRY FOR EVERYTHING!" Miraculously, their circle of friends overhears or learns of this somehow, and because apologies heal all wounds, all is well.
Pretty sure you just described every other episode of Saved By The Bell. Zack acts like an asshole, he loses his friends, he apologizes, all is good. I can think of a couple right off the top of my head:
1. The one episode where he sabotages the baking competition against the girl team
2. The one episode where he sabotages the glee club school contest
3. The one episode where he sabotaged the golf cart that Slater was driving and kelly got knocked in the head with a locker
Actually, Zack is a huge asshole.