1. They are hilarious. (e.g.: Edbear attempting to slide down the concrete path on his butt as if it were a playground slide. Did not work that great.)
2. They think you are hilarious. Pratfalls, funny faces, pretending light things are heavy, anthropomorphizing inanimate objects, pushing a towel on a swing. They eat it up so heartily you start thinking "Man am I funny. I should charge for this comedy gold."
3. It's good exercise. "Run with meeeee! Chase meeee! Go get the balls I keep hitting into the street! Heave my 30-pound body into the air!" Who knew the best personal trainers were the ones that stare up at you with an irresistably cute face and say "uppie, uppie!"
4. They are great appreciators of the finer things in life. Splashing in puddles, a good story, a bad fart joke, bacon. They are not capable of not living in the moment. Kids could give Thich Nhat Hanh a run for his money. If he had money.
5. They are gullible (see number 1). You can tell them anything! They don't know! The only limit is what your imagination can think of to tell them about where the boy on the bike is going or why the truck makes a beeping noise when it backs up.
6.They make you feel like a strong, omnipotent giant. In the workaday world you are just another shmoe. Around a kid you are Smelda, Viking God of Opening Things, Making Toys Function, Getting Out-of-Reach Objects, Fine Motor Skills, and Source of All Worldly Knowledge. (It's nice to have all the answers once in a while.)
7. A little body hurtled into your lap, or clinging to your side, is an excellent source of warmth.
8. You don't have to make small talk with them. They could give a crap. The real question is, will you or won't you take me outside to play.
9. Light-up sneakers.
10. Unabashed singing.