That's not meant to sound jaded; there are lots of things that matter in the world - and what's important differs for each of us.
Yet a lot of the stuff we're told is important growing up - not putting your elbows on the table, or being a "success", or not eating your dinner off the floor - are just constructs.
From the moment we're born we're taught the rules, and those rules so become part of who we are that it takes enormous energy to break them. Not having a degree in some way makes you defective. You're weird if you don't have kids. You must like The Beatles. Support our troops. The pressure to be what our world has deemed normal - or valuable - is immense.
If I was more cynical than I am, I'd suggest that society doesn't care what we do, so long as what we do serves to raise tax revenue, and not rock the boat.
The purpose we're all assigned is to help maintain the structure of our civilisation - but that's never explicitly stated, as it's too big and abstract an idea. Instead, society doles out invisible, unobtainable prizes upon which our feelings of worth can rise or fall.