Getting a PhD is hard work. But on my hardest days I remind myself that if it was easy, it wouldn't be worth much.
Today I found a verse in the Apocrypha that says it so well:
"The person who has what is hard to get rejoices more than the person who has what is plentiful." (2 Esdras 7:59b)
This is a helpful way of looking at lots of hard things in life. The most difficult seasons enable God to do the deepest work in us, if we let him. And jobs that are hardest to do bring the greatest rewards.