Glenn Quinn was in a 1995 indie movie where.....

he basically played Mark, but this time he was psychotic, not stupid and ignorant. It was called "Live Nude Girls" and he played the estranged "method actor" boyfriend of one of the main characters. And not only was he basically nuts, he was homophobic, too. In one scene he's demanding to be let in the house to see her and the flamboyant pool man comes out and says:

"May I help youuuu?"
"Who the hell are you?"
"Mr. French."
"Where's Marcie?"
"She's taking a long, hot soak in the tub and she's not receiving ANY gentleman callers."
"What are you, some kind of a fag?!"
*pool man looks at him in surprise and shock*
"Tell Marcie to get her butt out here right now!"
*I should add that the pool man is fairly large and muscular. He grabs the BF by the jacket*
"Listen you little soap opera reject, if you come near that woman again I'm gonna smash your pretty little face in, you understand?"
"OK, just let me go! *pool man releases him* "Slut!"

And that was Quinn's one scene in that film. His character was a real dick and Marcie regrets ever having gotten involved with him. Not a real stretch from Roseanne, huh? At least with Mark they made an attempt to give him a personality, but in this movie he was totally one-dimensional. Isn't that something!