There are so many good things about being an adult. You can literally go anywhere and do anything without anybody's permission. Nobody can ground you when you're living in your own place unless you break the law. The things that were holding you back when you were a teenager evaporate when you finally leave the house and start your own life.
While gaining independence is a huge benefit of adulthood, it's also a huge burden. You can't go everywhere and do everything if you don't have enough money to fund that. You don't have enough energy to go out so you're basically grounding yourself in your own home. You don't want to do the wild things you wanted to do when you were teenagers because partying all night is expensive and reckless. Most of us who've seen what adulthood can do to you love to complain about being an adult, as these hilarious adulting memes do.