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 compliment 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.
Hulk's Mundane Object Amazement with a soda can in "Ricky". The episode's titular character Ricky had to teach him how to open it and drink its content. Ricky being grateful and nice to Hulk also counts as a Heartwarming Moment.
To get access to the Culver University database, Bruce poses as a pizza delivery boy, and along the way bribes a guard with a pizza to let him in. After a tense moment of him approaching the computer lab and having a flashback to the experiment that turned him into the Hulk, Bruce sits down at a computer... and looks across the room to where a student, the only other occupant of the room, is munching on some pizza that Bruce bribed him with, and lifts the slice as if saying "cheers".
General Ross: "[Bruce Banner] is a scientist. He is not one of us."
At one point, on the computer Bruce is using, a Norton anti-virus software opens up. It's just delicious irony, because of the actor's name (Edward Norton) being synonymous with Bruce's struggle being the Hulk!
When Hulk is startled by Betty in the cave he hits his head on the low ceiling. Instead of freaking out and smashing the cave he rubs his head, grumbles and turns around looking embarrassed.
Even funnier, his pose when he walks out into the rain. He rubs his head, cocks a hip, and puts a hand on it.You can almost hear him thinking "Women" in an exasperated tone.
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.
And her reaction when his heart rate monitor beeps as it goes back to normal.
Betty: (disappointed) Not even a little excited? Please?
Bruce realizes to his horror that he isn't turning into the Hulk right after jumping out of a helicopter.
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.