It's a norms vs needs distinction. When you're a baby you don't even know that you have to sleep to not feel tired, or eat to not feel hungry. You learn pretty

It's a norms vs needs distinction. When you're a baby you don't even know that you have to sleep to not feel tired, or eat to not feel hungry. You learn pretty quickly but at first you're just always upset that you feel these things and cry about it, so your parents(if they are any good) will try to normalize bedtimes and mealtimes to speed along the concept. It's not exactly different for the twenty-something going on thirty, just so much more complex that the presented norms never really fit anyone. Things like what ideas are worth studying, what to look for in a relationship, what the "good life" is - those are quite subtle concepts.