I see all kinds of funny stuff in Animal Crossing, but a few are my real personal favorites, such as one time when I was at Club Lol to get a song from K.K. and then one of the animals, a kangaroo named Mathilda, said she hoped K.K. would take off his shirt and throw it to her. Then she remembered he doesn't wear a shirt.
Another time after I woke up Gulliver on the beach he asked If I was the sweet princess who kissed and awoke him from his slumber, and then he's shocked and exclaims "Wait a minute, you don't look like no princess!"
It was even funnier because I play as both a boy and a girl villager in the game, and at that time I was the boy.
Another time I found Isabelle asleep at her desk. My female character who is the mayor, woke her up and she said, "It's not what it looks like... oh okay, it's exactly what it looks like, but I was dreaming about work! Honest!"
It's also possibly the most adorable thing she's done in the entire game.
Kapp'n will sometimes sing about how he toots more than his own horn. Must be the cucumbers he likes so much. Another time he said he doesn't know why, but when people tell his daughter she looks just like him, she starts crying for some reason. Also if you push the A-button repeatedly, you can skip his song and go straight to the island or back home, but he'll complain a bit before you do.