I'm a big fan of the SQ cabin crew and although I would prefer to be on a plane with all female FAs I would choose an all male SQ flight over any AA flight I have EVER been on.
I find the transatlantic ones with AA are the worst. I am scared to even speak to the FAs on these. I limited my communications to answering the question with a "please" and subsequent "thank you's". Despite this I was shouted at once because the FA could not understand my (Scottish) accent. Sorry for not being from the mid west!
I would never dream of so much as asking if I could keep the whole can.
Only part of it is SQ's hiring practices - the bulk of it IMHO is that they still view their customers as passengers and not troublesome pieces of air freight.