The most irritating thing in BKK is when you come to immigration, either arriving or leaving, and you see long queues of passengers, and substantial percentage of immigration counters unstaffed. The absolute waiting time may not be any longer on average vs other main airports, however it just irritating to wait in queue in such situation, and makes the whole airport operation feel like being run by idiots not caring about their cash-bringing visitors. Other that that, I agree bkk is okay.