Life is how you take it, Lyn.
I used to hate it until I learned how to focus on the good moments:
taking just a backpack (ez lightweight travel: 2 extra tshirts, socks, ...), doing online check-in to minimise the wait time, leveraging airport lounges, taking a shower in the lounge if possible, drinking enough water, taking enough entertainment with me (download youtube/netflix/... videos in advance), making sure to have noise canceling headphones (e.g. sony wh-1000xm5), have a portable powerbank and you are good to go!
Oh, and make sure to get a hotel to sleep over in between the flights whenever flight takes longer than 6 hours! Never take connecting flights unless you have business class on the plane and able to sleep in there.

I've learned the worst experience I had when I had too much of the luggage pieces with me, that's why backpack rules. And when I was too tired/sleep deprived/hungry. 

 Good point. Hating only doesn't help and makes everything even worse. I do integrate in my travel some of the points you mention. Upgrading the flight when there's a reasonable price, online checkins, entertainment... Never showered at the airport lol