The Mystery Cartoon Character Game, ongoing.

Still can't figure it out. Someone else knows this story.

I'm flummoxed as well. The first three clues had me thinking of Gromit, the sensible half of Wallace and Gromit's stop-motion short film A Close Shave. However, the next three contradict that.

Mr. Toad perhaps? He does steal a car in the book--whereas he's framed for it in the Disney version.

That's right, it's Mr. Toad.

You're up Glowworm.

Thanks, I had figured it out this morning before I had to go to work, but was certain someone would figure it out before I finally returned home.

1. I am an adolescent.
2. I don't react well to small setbacks.
3. I can get downright scary when I'm angry.

Hmm.. This is another that requires a lot of thought, and looking up.

I believe this is Katie Kaboom from Animaniacs.

Yep. "Her family knows that any time soon. Their little lady Katie goes Kaboom!"
1. Katie is a teenager.
2. Katie usually overreacts to small things--such as whether she can go to prom, or that the handsome, popular guy she's dating is actually a chicken. (Yeah, there was a Chicken Boo crossover.)
3. Katie literally becomes a monster when she's angry.

Found one.

I'm the antagonist in this movie.
I try to convince someone to let me marry his daughter.
I send my henchmen to kill off her love interest. (They failed)

I thought of two possibilities, but neither one fits the clues completely. So I'm stumped again.

I'm thinking this is the arrogant braggart Gaston from Disney's Beauty And The Beast. Villains don't come much more vainglorious, conceited and craven than Gaston. He tries to strongarm Belle's father, Maurice, into consigning his daughter to him; when Maurice rebuffs the idea, Gaston tries to have him sent to an insane asylum. Although the fawning sycophant Le Fou is Gaston's primary henchman, Gaston is able to motivate most of the townsfolk into a militia bent on storming the Beast's castle.

Good guess, but no. It's not Gaston. My character has more than one official henchman.

OK, here are some more.

The whole town is in danger of being destroyed.
I try and use this to my advantage concerning my proposal.
It almost worked.

Still don't have it, sorry to say.

Yeah, I'm not so sure on this one either.

Of course! My favourite movie - well, one of them!

It's C Bagley Beetle, from Mr Bug/Hoppity Goes To Town.

Pete, he's already on the list.

What the heck is going on with my computer?!? I checked the list and there was no character from Mr Bug Goes To Town! I just checked it again and there it was! Either I'm going bonkers, or I need a new computer.

OK peterhale, your guess is correct. Even though I messed up.

Don't think I deserve a point, as those who checked the list would have be deterred from giving the answer - but I'll take the turn...

1) My first outing is a trip to the zoo.
2) I am oblivious to danger.
3) My minder determines not to procreate.

This can only be one character. Sweet Pea, from the Popeye cartoons.