Inverse PTSD.
"The worst thing that's ever happened to you is the worst thing that's ever happened to you" — Joe Rogan
The saddest you've ever been is the saddest you've ever been. The hardest you've ever worked is the hardest you've ever worked.
Tough times aren't fun in the moment for the same reason that no one ever believes they're living through a golden era.
"The golden years" only ever seem to exist in the past because it's only with the benefit of hindsight that we know all our worries were a waste of time.
When you're going through it, all your concerns are still open loops, they're things to fear.
In retrospect you see that you had the ability to handle them and there was nothing to be bothered about.
Which suggests that if you've just come out of the hardest period of your life, this seems like a cause for celebration.
New workload level unlocked!
Every new challenge shows you a new territory you were scared of but survived.
Each time you break a new limit, you now know you have the capacity to handle more than you ever did before.
It's inverse PTSD.
Like workload exposure therapy that teaches you "Oh I've been here before and I didn't die, this is ok"