Sheeple herding and breeding.
Adult behavior is taking full responsibility for one's own actions and decisions, and doing whatever it takes to keep a roof over one's head and meet responsibilities to whatever dependents one has.
Texting and obsessing over celebrities.
Crosswords and Taxes
i am sure you don't want me to say it
There are a lot of adults in suit and ties that do not act adult.
Being grown up means you plan and you succeed on the goals you set, it means being not overly emotional on the down side, and just take it as it goes. It means when you screw up, you admit it and do better. You learn compassion, caring and sharing and it shows. You manage your money well,as in pay your bills on time, and thats about it.