In the comics, the Mask ruins people's lives the moment they put it on and become Big-Head. They're turned into psychopaths, kill or hurt anyone who annoys or had annoyed them and sometimes, they don't feel a moment of regret even when they pull the Mask off. Not to mention, all the chaos attracts the attention of police, criminal organizations and even other seemingly invincible killers like Walter.
The teacher may have humiliated Stanley as a kid, but the panel where she pleads for help after having broken her back shows that she's just a terrified old woman. And then Bighead/Stanley stomps his foot in her mouth deep enough to cut off her airway.
The moment in "I Pledge Allegiance to The Mask" when Kellaway returns to Edge City and learns that Lionel, his best friend and former partner, committed suicide two years prior.
Live-Action Film
In the movie during the big dance number. Dorian goes to talk to one of his men who had been shot by the cops, after The Mask beat them to the bank. He tries to offer him a smoke to comfort him, but he succumbs to the wound and dies. At first Dorian seems to take it well before he flies into a rage and chucks his Zippo at the TV. Of course it ends up being a Mood Whiplash when in his grief-induced rage he confronts The Mask at the club.
After Stanley is locked up in jail, he discovers that Milo followed him all the way to the station. Stanley tells Milo to forget about him and find a new family. But he just lays down near some garbage outside Stanley's cell whimpering for his master. It's one of the saddest scenes in the film.
Stanley: (softly and sadly) You better forget about me, buddy. Find yourself a new place to live. Looks like I'm going to be in here for a long, long time
The scene where Peggy and Stanley are talking about the mask after she helps him get away from the police. Stanley sounds utterly defeated and exhausted at how completely upside down his life has gone in just the past three days.
Peggy: I saw it. I saw everything. What's happening to you, Stanley? Stanley: It's crazy. I'm losing control. When I put that mask on... I can do anything. Be anything. But it's wrecking my life. My life is wrecked. Wrecked. Wrecked!
The look on Stanley's face when he learns Peggy sold him out. It's reminiscent of the look someone would give when they've been punched in the stomach.
Though it's a deleted scene, Peggy's death most definitely counts.
Even though he tends to be quite the JerkassBad Boss towards Stanley in the series, you actually can't help but feel kinda bad for Charlie in the Adventures of The Mask comic, "How The Mask Stole Christmas". Especially when you find out the reason whyhe hates the holiday.
Stanley Ipkiss, unlike in the movie where he ends up being with the woman he loves, doesn't have much success with any woman he comes across and any woman he does end up with is chased away by his masked alter ego The Mask. Stanley is taken advantage of by people like his friend Charlie, who is a Bad Boss towards him. He also's the Only Sane Man as well as the police are acting like idiots at times with Kellaway being on his case.
The Mask, despite being well-liked and loved by most people in Edge City, does not have any luck with women at all. He knows he can be around forever by not taking his face off, but he doesn't want to do that to Stanley, since he cares about and loves him very much.
When The Mask was framed for stealing from orphans and everyone believed it. The Mask is one who casually shrugs off insults and threats with a happy-go-lucky attitude. Being shunned and hated by everyone including innocent children left him speechless and subdued.
