Some people like intellectual challenges and others like to test their physical abilities.
Do any NFs look for or put themselves into situations that will stretch their emotional boundaries? This could be personally or interpersonally. This doesn't exclusively mean dealing with difficult people (although it can) or putting yourself in an unhealthy or destructive place, but rather testing yourself and your emotional limitations. Basically, when others may quit and throw in the towel, do you soldier on not because of another person, but because you want to know if you'll survive?
Yeah, I can't think of any examples so feel free to give me some.