This airport is very near Mount Everest, in fact it's named Tenzing-Hillary Airport after the first two people to reach the summit. For climbers it's popular to fly in here and then ascend on foot to Base Camp. Interestingly, the airport has killed more people than the mountain.
While the statistics don't sound all that inviting and the structure of the runway not, well... optimal; I would gladly visit this airport. Nepal is towards the top of a long list of places I want to visit. Worlds scariest airport is a subjective thing though. I would be more afraid of human behavior than challenging terrain or rough runways. Meaning that as an American I would be scared in Iran, North Korea and other places where it's not exactly a boon to be from the "West".