This is extremely true. I remember at one point I get used to work till late and wake up late in the morning (aka, early in the afternoon), going to bed regular

This is extremely true. I remember at one point I get used to work till late and wake up late in the morning (aka, early in the afternoon), going to bed regularly at 6am and waking up at 2pm - at that point I literally shifted my day into another timezone. By working late, relaxed and concentrated, it easy to get you body used to it: the coolest thing is that it makes you get into the flow in a couple of minutes. And boom, I started one of the most productive period of my life. And yes, I was really productive, and yes I did some really good coding, but I felt like I was messing up my life. I discovered the morning has a value, both from a health/social perspective, so now I'm constantly trying to sleep between 7/8 hours and sleep not later than 3am. And I'm imposing myself to get used to 2am in the next couple of weeks.