Because Sao Paulo is I believe, almost the worlds most populated city. It's enormous. You are 30 miles out at about 12,000 on the approach flying over skyscrapers, and 30 miles later you land having flown all the way over skyscrapers. Quite a staggering sight. What has busy airports and being tight and unforgiving got to do with each other? There is no connection. Don't understand what your last line means.