Caillou is a 4-year old boy and the titular main protagonist of the Canadian animated TV series Caillou.
- To start off the list, he is infamous for his constant whining and pointless temper tantrums. Most infamously, he had a meltdown after finding out that he was going to the circus tomorrow when he thought it was today. Not next week, not next year, but tomorrow. This obviously proves he cannot handle not going to the circus.
- These temper tantrums got so out of hand that many parents complained about their children's behavior changing after they watched Caillou.
- His second most infamous temper tantrum was in the episode Caillou's Teddy Shirt, in that clip of Rosie wearing his teddy shirt, he has to have a stupid meltdown all because of that. He even shouted at Doris really loudly that the whole house could hear him. And when Doris told him that it was too small for him, he just shouted back at her by saying ”NO! IT'S NOT TOO SMALL FOR ME!” when it actually was too small for him.
- His voice is grating, especially when it was provided by the late Jaclyn Linetsky and when he cries.
- On that note, his crying will most likely get on your nerves.
- He is selfish and often does not like to share.
- He is cruel to his little sister Rosie, even going as far as pinching her in the face in "Big Brother Caillou" (and he acts even more spiteful in the book version by biting her).
- He became a Gary Stu in Seasons 4 and 5, as he is given a blander characterization.
- When he is not being bad, he is kind of cute sometimes, and there are some episodes where he is nice and helps out.
- He sometimes does teach decent life lessons about social skills and exploring the world.
- He actually has some character development. He matured himself since Season 4-5, despite having some moments of not sharing, and didn't cry at all in Season 5 and onward.
- He cried only once in and only cried in one episode of season 4 called "Caillou the Patient", he fell on the knees and scraped them, which is kind of a reason of a young kid like him to cry.
When the book series started in 1987, Caillou was a baby, but when it was time for him to age up, the illustrator found that giving Caillou hair would've made him unrecognizable, thus explaining the character's baldness.