Lack of independence & responsibility: There is nothing like picking up responsibilities at a younger age. This of course is less likely to happen unless you get out of the cocoon and learn things the hard way! Whether it is managing living expenses or your day-to-day chores or balancing study/work and home. You realize the financial pinch and learn why parents always stressed so much on saving money.
No privacy: There could be several exceptions where parents are super cool and your privacy is not hindered. But let's admit it, in most cases, you have to say good-bye to it when you're with your parents. House parties or blasting loud music is never the same with parents.
Timelines & Restrictions: Your nightlife ends at a time that your parents decide. In certain cases your parents decide who you can be friends with. Most of your travel plans will need approvals or need to be faked as study tours. You cannot watch your favorite TV shows either because your parents think that western culture is affecting your life. F-TV is a strict No-No.
Dependency: You will never learn to be self-dependent as long as you have your parents around you. Only when you're on your own you realize how dependent you're on them for the tiniest things. Learning this at a younger age specially in 20s is the most crucial thing.