Or arriving at airports in any number of poorer countries. I've been in over 40 countries for work and tourism. GRU is no gem, but if OP finds it one of the most disgusting in the world, they've led a (thankfully) sheltered life in terms of travel. OP says they were in a "hot, crowded" first class club. No AC? I can just imagine if they were in some small airport in parts of Africa or Asia, or even more basic airports in Brazil, such as Teresina and Fortaleza. Even finding a first class club sounds like progress, but maybe OP should avoid flying to Brazil. There are places with, in general, more comfortable airports.