I'm 37 and have no kids. That being said, I won't answer the phone on Father's Day if I don't recognize the number.
I really enjoy being an uncle; both to my sister's kids and to my friends kids who also call me "uncle Ken." I can spoil them at Christmas/bithdays, take them to do fun things that they don't get to do all the time. (Like what happens at the driving range if you hit 6 balls at once? I don't know- let's find out!)
Sometimes it's good to be single.
Oh, and completely unrelated, I am sure looking forward to going to Arizona next week to see 4 different major sporting events in one weekend.