This actually depends on different people see it from their own prespective and experiences so that list cannot be trusted completely and opinions will vary.I personally think Delhi Airport has been vastly improved and it adheres to world class specifications when it comes to passenger comfort.Most US airports have this extra security check which is part of Homeland Security strategies.Most Asian as well as Arab airports have many problems like bribery,disorderly conditions and poor management but improvements are bieng made in all aspects.