I don’t think the poster was saying they don’t feel like crap after such a long trip. Of course they do. The point was that they behave like grown-ups and get through it quickly, as they supposedly chose to travel and nobody forced them to.
Sometimes in life we have to do things that are a bit difficult. I’m astonished at how many adults seem unable to understand this concept, they must have led very sheltered lives.
I have a friend who has to travel for work to the other side of the world every 2-3 months. They moan for about a week going there, another week coming back, how sleep deprived they are, and tired, and jet lagged, and unable to function. Yet they don’t even try to regulate the time difference, or to go to bed earlier / stop the coffee past X time. They don’t listen to any advice they themselves have asked for. Just stay awake for a couple extra hours on the first few nights and be done with it (yes I deal with jet lag regularly too and I know it’s a killer, but there are things you must do to mitigate it).
Some people would rather complain for days on end about something, rather than choose to do one little thing that’s inconvenient short-term, but ultimately more rewarding.
OP could go to sleep at 10pm having packed and showered, be up at 4am and in the airport by 4:15. That’s 6 hours of sleep which is a decent enough for any reasonably healthy adult. Make up and browsing duty free are not essentials at 4 in the morning. She could inconvenience herself by skipping those, but she’d rather moan about the whole thing instead.