I never understood how other people's suffering will somehow make one feel better; it will usually just make him feel bad for others and make him feel more guilt.
Anyway, people compare their positions to those that are similarly situated. For example: I don't compare my lot to amputees in Cambodia, but to other law students in Winnipeg. A visit to Cambodia would only temporarily change that, once back home, it's back to comparing myself to my peers; and consequently, feeling a sense of deprivation.