He's go to be the most annoying children's show character ever. That's saying a lot, when you consider just how many kids characters have zero redeeming qualities.
He whines, about just about everything, everywhere. Relentlessly. https://youtu.be/cGo60pp_9IM?t=6m30s It got really annoying when my wife and I watched it with some of my nieces (and saw how the show influenced their behaviour) that when we had kids of our own we agreed that we'd never allow them to watch Caillou.