EVERY scene involving Melissa McCarthy's Megan. Her sincere and somewhat deadpan deliveries help, no wonder she was nominated for BEST supporting actress:
Her driving by Annie with 9 puppies in the car and a Slasher Smile
Her idea for Lillian's bridal shower: A female Fight Club where everyone surprises Lillian by not telling her the theme and then beating on her. Everyone's reaction just makes the scene all the sweeter.
"THIS IS LIFE, ANNIE!"
The sex tape with the Air Marshal that cuts into the Dance Party Ending during the credits
"I took two puppies. They're in my van."
Her constant badgering of her seatmate on the plane, thinking he's an air marshal. Which is actually true, to her delight.
"I'm glad you're not with him because I'm gonna climb him like a tree"
"I can't protect you. I know where all the nukes are, and I know the codes. You would be amazed, a lot of shopping malls. Do NOT repeat that."
"I own 6 houses and an eighteen-wheeler that I bought just because I wanted to."
"I snuck a loaded handgun into Dougie's luggage. The TSA is gonna tear his ass up."
Her very first speech to Annie, talking about how she fell off a cruise ship and communicated with a dolphin "I'm gonna say, telepathically?"
Becca's drunken compliments - "You-you're more beautiful than Cinderella! You smell like pine needles and a face that looks like SUNSHINE!"
Annie breaking every car law she can in order to get Nathan's attention
Nathan's deadpan response ignoring her: "Let's see what Marmaduke's up to."
Lillian's Dad: I wish they'd just get married right now, just to save me a shitload of money. (Everyone laughs). I'm not joking. (Everyone laughs again). I'm not joking. (Everyone laughs one more time).
The plane scene (along with others) is arguably an Overly-Long Gag, but parts are excellent, such as a drunken Annie demanding that they keep the curtain between coach and first class open "because it's civil rights. This is the '90s."
Pretty much any scene with Annie's roommates.
You're really doin' it.... You're shittin' in the street...
That entire scene where the bridesmaids succumb to food poisoning while in a very fancy dress shop is too hilarious to put into words.
On first meeting Nathan, who's a police officer, Annie tries to prove to him that she wasn't driving drunk by... performing an odd yet nicely choreographed dance routine along the road's white line.
"Lillian...*stares at Lillian*"
Annie's (rather justified) tantrum at Lillian's bridal shower.