There are things that have changed drastically since I became a parent, and I know that I am not alone in this. As a parent, you often find that you are doing and saying things that you swore you would never do. Open your mouth, and the words that come out of your mouth were plagiarized from your mother. A true, "Oh my God, I'm turning into my mother" moment. And that is not the only thing. All that cool stuff you did as a teenager? All your friends who knew you back then are under a gag order when your child is anywhere within hearing distance because you do not want them copying you. Put firecrackers in the neighbor's mailbox? Don't say it around the kids, they'll want to one-up you. You morph into this spastic person who doesn't blink an eye at the insanity that is parenting; the old you is still there, but is at war with the parent you, causing some pretty insane behavior.
An example of this is when you are with your sister's kids, and the nephew starts licking your daughter and niece's faces, so you decide the punishment must fit the crime, and lick your nephew's grubby-ass face, and then decided that licking your germaphobe sister's face would be pretty freaking awesome, which does nothing to stop the nephew from licking people, and in fact, spurs him to greater measures. You remember things like when you were a kid and used to climb onto the top of the roof and the car port, and then jump off, because why the hell not, but now you spaz-out when your daughter leans over a railing. These are all signs of your old personality and your parent personality fighting for dominance inside your brain.
Remember all that crap food you used to consume by the cart load? Eating spaghetti used to count as vegetables with me. There's tomatoes and stuff in that, right? Now I wage war with the kiddo, trying to convince her to eat more green stuff, because I'm convinced she doesn't eat enough veggies and her little ass is gonna get scurvy. Want a change in dinner? Try and convince the kiddo of that. By now I've eaten enough chicken that I wouldn't be surprised if I sprouted feathers and started flying, because chicken is her favorite.
Being a parent is watching more kiddo shows than you watched even when you were a kiddo yourself and swearing that if you ever meet a Wiggle, Barney, Teletubby, or any other similar TV character, you are going to take them DOWN, for the good of all mankind. Being a parent is when you've changed your kiddo's diaper and had the kiddo SHIT all over your hand, and the primary feeling you felt was relief because they weren't bound up anymore. When you go stand in the public bathroom line five times in thirty minutes because you are potty training your kiddo and they are in big kid undies. When you learn to like whole wheat bread because their doctor has said that your kid needs more fiber, and finding yourself actually reading the effing nutrition label to make sure the stupid whole wheat bread you are buying actually is high in fiber after you learn that some of the whole-wheat options are just white bread in disguise. Being a parent is suffering through your kids being grounded and having privileges taken away, even though that shit is harder on you then it is on the kid, and after hearing them whine "I'm bored" and "This sucks" one more time, you want to remove your eardrums with the screwdriver, and knowing that a in your pre-parenting days, you would have thought that the shit they pulled was no big deal and might have even been impressed. Being a parent is being pulled in two by the wish that they would stay young forever and the desire for them to grow up and show the world what they are made of.
The truth is, that no sane, normal person can function as a parent. You have to be truly insane to be able to manage the multiple personalities waging war inside your body. You have to learn how to be firm with your kid, and discipline them and make them follow the frickin rules, but you also have to not be someone that they are afraid to talk to when they need help, and that is a hard person to be, and a person like that needs to have multiple personalities just to function. This is the truth of every parent. We may have started out as sane people, but we sure as hell aren't sane now.