Afternoon naps
The only constant I have observed in my 21 years of existence is this — no matter how well I sleep at night, it just won't be as good as that nap in the afternoon.
I'm a Bengali. And what science suggests is that since Bengalis have a carbohydrate-heavy diet, food that takes long to digest, they're naturally more sleepy. This makes sense to me. Everyone in my family sleeps in the afternoon just as they do any other task during the day. You have a certain time for food, a certain time for work, and a certain time allocated for, drumroll, yep, that afternoon nap.
The nap is beautiful. Nothing hits like it. Nothing compares. Nothing comes close. It's only later in the night when I start to regret it. That 3 hour nap (yes, I nap for 3 hours and yes, a 3 hour nap is still a nap) causes my sleep cycle to go haywire. So instead of being fast asleep at 10pm, I'm sitting in bed, eyes wide open and mind wondering why, just why did I take the goddamn nap in the afternoon.
People learn from mistakes. Not me, though. I know naps mess up my sleep. Do I stop? No. I've learnt to enjoy the nap whenever I have the opportunity. Because no matter what, I will, of course, eventually fall asleep at night, so...