I wouldn't say they move fast. They just move consistantly.
Irileth, my corn, was hanging out with me during a school presentation. During my introduction and 'rules' for how to interact with the animals, she proceeded to go up over my shoulder, around my neck, up into my hair, down under my arm, around my waist and back to my hands. It wasn't fast, but she was definitely persistant about wanting to explore, haha. The kids thought it was hilarious when she was peeking up from behind my head, holding onto my ponytail.
Hence why they are cool for kids. Irileth will come out and watch me if I'm moving around by her enclosure. Interactive is a word that comes to mind to describe her. Not like a dog or a cat, but about as much as my leopard gecko :gj: