Originally Posted by
klakhav
Are there any lounges open 24 hours a day? All night lounges?
Why don't you just do what this guy did: Singapore airport says there are so many bars, you could never drink at them all between planes.
http://lux-traveller.com/2017/singapore-airport-bars-drinking.htm
With determination, you can spend all night on a pub crawl of every bar in the airport on a Singapore stopover.