There's no way you're going to get to see everything that your kids want to see if you don't get to Disneyland as soon as it opens. Of course trying to explain that to them while you're attempting to get them out of bed is another story. Grown ups don't really have this issue because we're more than willing to miss some experiences in order to stay in bed.
#9) Don't Have to Carry Anyone
There's nothing like that moment when your kids decide that they just can't walk another step, especially when that realization hits them in the middle of a fast moving walkway. I am assuming that your lack of children hasn't led you to spend the day consuming adult beverages. If that's the case, this one may not apply.
#8) Don't Have to Line Up for Hours to Visit Characters
Another "Your Mileage May Vary" situation here, as if you happen to be married to my wife (and you'd better not be), you're lining up anyways. Even she has limits though. Two hours to get a picture of a girl dressed up in something green with wings on her back is not the Tinkerbell experience she's looking for.
#7) Don't Have to Get Wet
#6) Don't Have to Spin
#5) Don't Have to Explain the Reference
Not to pick on Splash Mountain again, but I've kind of grown tired of explaining who Brer Fox and Brer Rabbit are. Same problem for the little bit that the Chronicles of Narnia characters were making appearances. There is a flip side to this one though, as Nickelodeon parks tend to puzzle me to no end (Why are we lining up to get our picture taken with a squid and a sponge?)
#4) Don't Have to Eat Churros for Every Meal
When we went to Disneyland before we had kids, we would eat wonderful meals. My favorite was at the Blue Bayou inside Pirates of the Caribbean, it was fantastic! Now our meals tend to consist of Mickey ice cream bars and churros, and actually that's pretty great too. I guess you could eat churros for every meal, you just don't have to.
#3) Don't Have to Lose at Scoring Games
#2) Don't Have to Fit Into Rides That Aren't Meant for Grownups
I hate when my kids want to go on rides in the little kid section. I'm a bigger guy, and if I can squeeze myself on to the Casey Jr. Circus Train then Cirque du Soleil needs to come calling. I refuse to ride Dumbo anymore because I don't want to be that guy whose elephant can't get off the ground.
#1) Don't Have to Sit Down Front
I don't know what age you finally figure out that the front row isn't necessarily the best place to sit, but I hope that age comes soon. Sure it's great to be close for some shows, but sometimes the view can actually be worse if you're sitting too close. For example, my daughter once insisted that we sit in the front row for the Shamu show at Sea World in San Diego. Not only is it impossible to see half the show from those seats, do you know what happens to people in the front row....