Basically, growing up is almost a necessity in survival in today's times. Being responsible and not doing stupid shit will get you a long way.
Growing out of the immature "I WANT IT NOW" mindset with more expensive items (such as big screen TVs, the latest gaming system or other crap) is important. Otherwise, people just sign up for a credit card and accumulate so much debt/interest that they cannot possibly ever hope to escape from it, to the point where they have to almost completely restart their lives through bankruptcy. When choosing a place to live, living within ones price range and not getting an overpriced apartment/home that one can barely afford is generally something to do. Although controllable debt isn't a terrible thing.
Socially speaking, I naturally mean being mature enough to realize that this isn't high school/elementary school anymore. There are just some things that aren't "funny" once you've hit a certain age. Drinking/partying all hours of the night and going into work is not a generally good thing to do as you age. Having protected "relations" (should one choose to be active in this regard) is also important unless you want children to be responsible for. Oh, and I honestly think social media responsibility fits in here too. Quit putting stupid "OMG I H8 MAH BOSS" on your personal Facebook/Twitter. Anyone can see that stuff, and you are ruining your chances for employment.
Speaking from a business perspective, growing up in "fashion" is also something that is necessary. Suggestive T-Shirts or baggy jeans are a big ol' no-no. Not saying that wearing that kind of stuff on one's own personal time/dime is wrong, but when at work or meeting co-workers/clientele in public, appearance is everything and first impressions are very powerful. (You would THINK this would be obvious, but it is NOT to many people I've been involved with)
So in the most basic form, surviving in today's economy and world is very dependent on one's ability to mature and grow up.
EDIT: All of this is null and void if your name ends in Kardashian or Hilton. >_>