For those of you looking to Fedex in particular or freight in general. He's some observations from a 54 year who's been doing this a couple of years.

Domestic hub turns.

This applies manly to the start Monday, end weekend night stuff. First night of flying (typically, Monday night/Tuesday morning) is the hardest. No one is acclimated even though you had a legal "rest" before the flight. An extended duty day (due to wx or system problem) would make this a bad start to the week. Things slowly improve as the week goes on.
When you can hold day hub turns you will see a whole different crowd of pilot. Better rested but you get no meaningful layover. You will get to know the ops area in Memphis because of the very long hub turn. Join the gym, you'll have time and may even fit in an afternoon siesta!

International.

Memphis based. Lots off variety, but I'll concentrate on the long stuff because we have a lot and commuters prefer them.
A round the world Westbound. Easier than Eastbound. Recovery for my 54 year old bones, is three days minimum. When younger was easier. YMMV.
Eastbound around the world. Harder than Westbound, enough said.
Slingshot. Go east till you hit China than reverse course. Not sure what to make of this type sequence (from a jet lag/sleep standpoint). Good news: if you like Europe, you get it twice in the same trip!

If you get Anchorage based and you live there, you'll have a more civilized start to your Asian trip. You start in the morning, fly in daylight and arrival the day after you left. All bets are off after that for rest/jet lag.

Thats it in a nutshell. lots of other stuff. Look around, others have written or will write in the future. Just ask!l