I think everyone is different. For me, I absolutely love isolation, and a week or two in the high country all by myself literally invigorates my soul. As far as the fortitude to keep going aspect, again for me, I think it comes down to a couple of things. One, is how passionate you are for hunting/nature/wild places. If its a casual thing or even if deep down you find you would rather be golfing or fishing or playing video games, then its going to definitely be harder to push yourself when things get hard. The second thing is preparing yourself throughout the year to be "Comfortable being Uncomfortable". This is a huge part of my ability to weather hard times in the backcountry. Even if you live in suburbia, or on the east coast, look outside. Temps below freezing? Its raining cats and dogs? Its snowing hard? Grab your backpack and go for a ruck. Throw your running shoes on and go for a run. Intentionally put yourself in uncomfortable situations throughout the year to build that muscle memory. Then, when that high country storm blows in and the temps drop 40 degrees in an hour, its not going to be such a shock to your system. Again, everyone is different and what motivates me doesn't necessarily motivate the next guy.