Not everybody grows up when they grow up. None of us mature the moment we get wise counsel. But, the wise among us can plant “wisdom seeds” of a happy life.
Don’t hate or fret over the idiots in your life. In some sense, you’ve been that idiot before and you probably will be again. Rather, take your frustration with other people’s immaturity to a constructive venue: keep planting wisdom seeds and keep dripping water on those seeds.
Adults are brats because the adults in their lives didn’t drip wisdom. You be their adult and they just might grow up.