Saying that C3PO card can't be proven to be faked is like saying that we couldn't prove Barry Bonds was on steroids.
I'll second what E had to say about parenting. There is some downtime involved, especially when they start exploring their own imagination and personal playtime/space. I get most of my school reading done in these bits of time during the day. That being so, there are some significant schedule demands like waking up when the kid wakes up, making sure you're feeding them 4-5 meals a day.. getting excercise, reading books, so on and so forth. Plus, the whole "going out on a whim" thing kind of doesn't exist anymore without also planning on dragging along all of the related baby gear.
Seriously though, I think the parental instinct kicks in and you just don't mind the shift in responsibility and focus. It's fun being a kid again (even though she wears me out.. LOL.. I dunno where they get all that energy. I swear she could run full speed for 3 days straight)
On that note.. Gotta go make some grilled cheese and chocolate shakes. Weeee!
=)