The second episode of Assange's show
When villains are too evil
I first noticed this in The Cowboy Way. Woody Harrelson, Jack Bauer, and Winston Zeddimore are rescuing the daughter of an old friend. Said daughter has been kidnapped by a sweatshop owner who specialized in smuggling illegal aliens into New York and then enslaving them. At this point in the movie he's been brought low. His work is gone, he's been exposed, but he could get away and come back for revenge...
If he weren't so dedicated to hanging onto that one girl. He refuses to let her go, even after she becomes a liability. This is what I mean by villains needing their own goals, instead of just opposing the heroes. His goal is to get away, but since he's the bad guy he has to act stupidly evil.
The same is true for Gaston. When Maurice bursts in claiming Belle has been kidnapped by a Beast with huge fangs, fur, so on, no one thinks, "hey, maybe it's a wolf." Worse, seeing as they all think Maurice is crazy, Gaston never even looks for Belle.
Even putting aside the wolf, there's a reasonable chance Maurice, whom everyone agrees is nuts, killed Belle and is trying to divert suspicion. If Gaston were any less lazy, he could track Belle down (as the bar just sang about how awesome at hunting he is) and probably save her before she decides Beast is her friend. Instead, he went straight to villainy.