Back to the question "Can we build toughness?" If toughness is defined as completing a difficult task without fanfare or complaint, then I say yes. But it doesn't come without practice in the techniques.

One thing that continually comes up is to break the difficult into small doable tasks and just focus on that. For me, it's better to unfocus until each task completed.

For instance, if I have a long day ahead of me, I might decide to stop for a drink and a snack every hour. (This time was shorter at the beginning of the season when my pack was heavier.)

I set this time to be BEFORE I knew I'd need it.

The snack and drink are a reward in my mind for hiking the distance. Eventually, the two get mixed up in my mind and the distance is also the reward.

For my son, the reward is to take pictures of the great views at the top of the hill. So he likes to push uphill, stop and take pictures. Then meander downhill.