My favorite parts in MU include:
“Hahaha, please don’t call me Karen -_-;;”
“I can’t go back to jail!”
“I’m a dance major!” “…and I’m not .-.”
And when Art is all excited and hands them dream journals. Cracked me up 
There were many other parts that had me snickering, but those I remember the most. Also, I love Art, he is probably one of my favs…
I remember watching Monsters University and I was the only person who laughed in the theatre when they’re taking the final after the first semester and a bunch of the seats were empty. Not sure if it was intentional, but I’ve had college classes where half the students dropped by the end of the semester and seeing that just made me laugh.
mo: That’s happened to me in some of my classes! Especially if they’re Math of English classes. I was always one of the few that pulled through, while everyone else dropped.
And it’s great to see you on the forums once again!!! I’m pretty sure a lot of people around here have missed you, including me.
I NOTICED THAT TOO.
That never occurred to me. 
I thought they just had a lot of time to practice before they had to scare.
Another thing about the Pixar films that make me laugh are all the little sight gags.
“Send her to the repair ward. And have them run diagnostics on her. Make sure she’s not…”
And then Captain B McCrea suddenly (but very slightly) freaks out.
And also…
Jack-Jack floating up to the ceiling, with Kari freaking out after Jack-Jack opens his baby bottle and spills his milk right on her shirt!
Okay, I’ll admit it: The scene where one of the grasshoppers finds Dot’s bandana, puts it on his head, and mentions something about keeping dry in the rain.
^That scene in ABL makes me laugh, too! I love how frank that second grasshopper was…
Puts on bandana “How do I look?”
“Like an idiot.” 
My sister just told me today that her favorite part in Toy Story of Terror was when the Pez threw up its candy.
Ok, I know you guys will probably shun me for this one, but…
The newspaper about the party in Monsters University
was actually funny, despite [spoil]being a mean prank by the ROR fraternity.[/spoil]
It was a genuinely funny scene, especially considering what actually happened wasn’t really that awful.
Actually, they were being teased for being different and it just wasn’t very nice.
Which is why they had to go to watch the scare floor and find out that there is no “one type of scarer”. A good example in one of many ways that Pixar can put some really valuable life lessons into their films (especially considering the fact that their two main themes are always about friendship and love…and in very unusual ways, too–considering that the majority of all Pixar characters are not really people at all, but they somehow are still able to possess such qualities)
Don’t feel bad about it, JSWeC. I chuckled a bit at that part and then felt bad for laughing. MU certainly has itself some funny moments that I feel bad for laughing at sometimes. Like the whole [spoil]“I can’t feel my anything!” bit; I feel bad for Squishy because of the circumstances, but that line just makes me die laughing.[/spoil] I really hope nobody in the theater thought I was a jerk for doing so… Anyway, the fact that Pixar can so quickly switch from laughs to tears is one of the reasons I love their movies so much 
Pretty much everything you see in the majority of short films:
(1) Kari freaking out when Jack-Jack bursts into flames
(2) When Bass and Treble stare at the fountain
(3) When the light goes out again and BURN-E faints
(4) Mater panicking in his mad dash when he thinks he’s being chased by the Ghostlight
(5) Ken jumping up to the window when Bonnie leaves the house
(6) Stu getting frustrated over the so many buttons
it was really funny bc they were so kawaii. but it was sad too. I’m conflicted.
The fact that Lightning has little (rather adorable) stickers of himself in his trailer;
And Sulley has cinder-blocks in his room for no apparent reason;
^Wow, Villainess! I’ve never noticed that before!
Another thing that makes me laugh: That whole sequence within the Inside Out trailer (not the teaser, the dinner scene preview)
Villainess: Oh wow. I never actually paid attention to that (Sulley’s cinder blocks) Maybe he uses them for weight lifting or martial arts, or something along those lines.
Villainess: I think I agree with JustSoWall-eCrazy. I always thought the cinder blocks were exercise tools or something. Or it could be something as simple as a door stop. 
For me, Monsters inc is the funniest Pixar movie. When I think about it, my other fave Pixar movies all have tear jerker moments (Toy story 2 & 3, Up, Finding Nemo), but Monsters Inc is pretty much nonstop comedic gold, very creative and full of twists and a bizarre episode in the life of 2 working class monsters. I think the reason I like it so much is because it’s great without manipulating your emotions [of sadness]! If that makes any sense! The only sad bit was at the end when Sulley had to give up Boo.
There’s just too much comedy to list but:
“It’s, um, bring an obscure relative to work day.”
Roz, just Roz.
The musical! “Put that thing back where it came from or so help me!”
Randall’s lame geekiness and bad eyesight omg is his eyesight bad.
Randall’s sneeze.
Mike in general. He comprises 90% of the humor seriously.
When Sulley thought Boo was in the trash compound.
Mike: “How many kids you got in there?”
George Sanderson!
The Abominable snowman
“It’s lemon!”
“Nice, safe, Nepal.”
Mike and Sulley’s fear of Boo
The fruit loops and newspaper
Mike throwing snowballs at Sulley and hitting invisible Randall
Mike: “I know kid, he’s too sensitive.”
“Oh look, it’s Randall!! Oh…”
“Shh do you hear that? It’s the winds of change.” Made even funnier after MU
Randall trying to get Mike to put Boo in the door by lunch time; Mike is such a slow one
Other humor:
Toy Story 3: Spanish Buzz!
“Oh great, it’s the return of the astronut.”
Mr. Tortilla Head
Toy Story: “That was falling with style!”
“You are a sad, strange little man.”
Finding Nemo: Dory, Bubbles, vegetarian Sharks, John Ratzenberger
Monsters University also made my family laugh out loud, mostly because of Art, Squishy, Squishy ’ s mom and her romance with Don, also Young Sulley