Glory
Here it is: the reason you do this job. Sure, the wilds are nice and the travel is fun and getting paid certainly makes it better than your average hike, but you could have done that as a mountaineer, a travel writer, a park ranger, or a dozen other outdoorsy professions. You chose to be a leader of people. That means that even a tiny little part of you does it because you enjoy the praise.
Fear not, intrepid traveler, you can indeed get your narcissistic fill as an adventure travel leader. In the real world, you may be a quiet introvert, but out there, you get to play teacher, guide, healer, entertainer, team captain, chef, and wise sage all in the same day.
Did we mention their lives are in your hands? Because their lives are totally in your hands. Get them home safely with as many stories as possible, and they'll hold you up on a moss-covered pedestal for the rest of their lives.