In the episode "747", when the Hulk is unleashed on a plane, an airsick passenger gets up and opens a door...only to see the Hulk on the other side, snarling. He closes the door, terrified, and checks again. Hulk is still there. So he shuts the door and the Hulk retreats back down below like nothing happened. The passenger goes back to his seat and says "you're not gonna believe me".
In the episode "The Lottery", after Banner Hulks out halfway up an emergency ladder in a block of flats, he busts his way through the wall, and into a room with a couple looking on in shock and confusion. He then bursts through another wall, and the scene cuts to a woman singing in a shower. The Hulk steps into the bathroom as the lady steps out, not noticing him and still singing away, wrapping a towel around herself. He looks down at her, then back up, and smirks before leaving the room by breaking down another wall. The scene ends with both the couple and the woman in the shower just looking on confused through the giant holes in the wall. It really has to be seen to be believed.
In the episode "My Favorite Magician", David assist a magician. In a show's number, he is handcuffed inside a glass box full of water. There should be a key in the box' false bottom, but the magician forgot to place it there. David hulks out and the Hulk appears to the audience... who applauds. Moments later, a middle-aged couple approaches Hulk outside the theater... and they cumpliment his performance. The lady wants an autograph and the husband takes a picture. When Hulk, annoyed by the camera's flash, roars at them and runs away, they simply think he's an eccentric artist. It can be seen here.
Once Bruce and Betty reach New York City looking for Mr. Blue, they contemplate the hazards of riding a subway full of typical New Yorkers and decide on taking a cab. This means a ride in the back of a cab driven by an extremely reckless Euro taxi driver whose antics nearly cause poor Bruce to hulk out from the stress. Even funnier, it's Betty who goes into full meltdown, as her first response is to scream at the taxi driver at the top of her lungs the moment they come to a stop. What sells it is the sound of Bruce's pulse watch bleeping down to safe level before:
After Blonsky knocks the Major out so that he can talk to (re: threaten) Sterns in private:
Emil Blonsky: She's an annoying bitch.
Samuel Sterns: Why are you always hitting people?!
Bruce messing up his classic line in Portuguese and frowning when he realizes it. "You wouldn't like it when I'm hungry. Wait, that doesn't sound right."
Before all the chaos starts, we get a peek of Bruce learning Portuguese by watching Sesame Street. It's seriously adorable.
Admit it. You laughed when the Hulk got pissed off and front kicked the ever loving shit out of Blonsky's arrogant ass.
The fact that Bruce couldn't make love to Betty isn't funny, but his exasperation upon discovering this fact is pretty amusing. The moment is then topped when she very sweetly consoles him after he tells her.
Bruce realizes to his horror that he isn't turning into the Hulk right after jumping out of a helicopter.
Ross: [To a soldier manning a minigun on the chopper] Use that thing, soldier, give him some hell!
Soldier: Which one?
Ross: [exasperated] Help the green one, damnit! Which one do you think? Cut the other one in half!
After the helicopter crash, Hulk walks over to see if Betty's okay, only for the Abomination to jump up from the wreckage ready for another round. Hulk rolls his eyes with an expression that screams "oh, come on".
The Stinger, where Tony Stark approaches General Ross in a bar. The scene itself is chuckle-worthy, but then the release of the One-Shot "The Consultant" gives it some context: following the events of the main movie, the World Security Council considers Blonsky a War Hero and wants SHIELD to send an agent to recruit him for the Avengers. Nick Fury hates the idea, so SHIELD hatches a plan to send someone to General Ross who will annoy him so much that he'll refuse to give them Blonsky. So Tony Stark walks into a bar...
Best of all is the punchline:
Agent Coulson: Apparently the Consultant outdid himself. Ross got so mad he tried to have him removed from the bar.
Agent Sitwell: How'd that go over?
Agent Coulson: Stark bought the place. It's scheduled for demolition on Thursday. [Agent Sitwell chuckles.]