Because you like Jake in Adventure Time
Linda Belcher doesn't prescribe to what society deems as "normal." She narrates her life through song, much to the alarm of everyone nearby. See them in Bob's Burgers.
Louise Belcher might be just a kid, but she can manipulate just about anyone with a pulse. All in the name of fun, of course. See them in Bob's Burgers.
Anger is a cantankerous hothead whose job is to get others riled up. See them in Inside Out.
The self-described "ghost with the most" knows the ins-and-outs of specter life like no other. Just ask him. See them in Beetlejuice.
Kyle Broflovski is an motional fourth-grader who plays Guitar Hero, speaks Pig Latin, and fights with his "Fat Ass" friend Cartman. See them in South Park.
Danny Zuko's car is auto-matic. Its system-matic. Its hyyyyydro-matic. Why, its greased lightning! See them in Grease.
Squidward Tentacles is a pretentious clarinet player in search of peace and quiet. See them in SpongeBob SquarePants.
Moe Szyslak is the crabby owner of the grimiest bar in Springfield. See them in The Simpsons.