He was downright funny (much more than Mater, to me).
I mean, he’s voiced by Billy Crystal, who is a comedic genius.
Well, at least Mike’s humor wasn’t about doing and saying stupid things like Mater.
Exactly.
I suppose it’s exactly like comparing the humor of Billy Crystal and Larry the Cable Guy in real life.
Mater’s humour derived a lot from the stereotypical redneck American, which is why I really, really didn’t like him. Pixar could’ve done something creative with him but instead they resorted to the first stereotype they could think of.
For me, Sully was definitely the main character. It was his storyline that was the main part of the plot, while Mike was mainly there to provide the comic relief and the occasional voice of reason.
I think people just don’t like that Larry the Cable Guy “brand” of humor. I think how Pixar used him in the second film made me lose some respect for the character.
I’ve always thought Sulley was the main character.
I’ve always considered Sulley to be the main character of the film. He’s the character that has the real moment of catharsis, or realization, when he sees how scared Boo is of him. Mike does have a moment of catharsis himself, when Sulley leaves the cave and Mike realizes how lonely he is without Sulley, but Sulley is connected much more to the story. He’s the one who found and cares for Boo, and he’s the driving force of the story. Heck, if Sulley hadn’t cared enough to get Boo back home and Mike had his way, they’d have ditched her and ran! So yeah, I definitely think that Sulley’s the main character. Although they still did a great job of giving equal attention to both characters throughout the film. 
Sully, no doubt about it.
Exactly. Not even a tiny doubt.
Sully, Mike is like the Willy Wonka while Sully is Charlie.
Sully definitely. The main story points all center around him
I’ve always seen the movie as being about Sully’s struggle and triumph over deciding to keep the human child or not–there’s more emotional weight placed on him and his development. So I see him as the main character.
Sulley…not sure why anyone would think it’s Mike. The movie clearly revolved the most around Sulley. Mike was more like his sidekick.
Sullivan, he was the reason why a lot of good things in the movie worked.
In Monsters Inc, Sulley.
In Monsters University, Mike.
That’s a perfect observation. You can always tell by asking who has the biggest character arc. Mike didn’t really “change” in Monsters, Inc.
While that works here, it’s not a norm.
Flik doesn’t change and still he’s the main character in A Bug’s Life. He makes everyone else change instead.
Okay, “usually”. 
I suppose in these terms, it’s the character who has the most effect on things or is followed the most.
Sullivan’s interactions in MI were the driving force for what happens.
Wazowski’s interactions in MU were what started and ended things.
And Randall’s interactions will be what goes into the sequel.
If there is a sequel. I really hope Mike and Randall can become friends again.