I prefer the Qantas on-board staff to SQ. Generally, the Qantas ones show initiative with kids, casually chat to customers and make you feel like your back in Aus as soon as you step on-board.
SQ staff are polite and efficient - however they're also meek, timid and lacking initiative.
Yes and no. I've found in recent times that I've had some casual chats with SQ staff too (mainly in J, not Y unless seated at exit row). I think points of reference help, and shared cultural factors, and it's a lot easier to have a conversation with someone if you have something in common, so it is natural that QF FA's have easier chats with Australian (or English!) passengers. With SQ I've found it easier to have such casual chats since living in Singapore, as there are points of reference we can talk about. More than just a few of them would be anything but meek and mild if you take them out of the constraints of their rigorous training. I've seen SQ staff behave in the same manner as QF staff when it comes to recalcitrant passengers (not stowing hand luggage, getting up before plane stops, etc), something that can't be said for some other SE Asian airlines.
II love it when FA's enjoy a bit of banter. On my recent international trips the QF Air Crews have been very good.
The banter thing can be a careful balance. One thing that I've seen a few too many times for my liking is QF crew (over) responding to a passenger or two they are enjoying a good conversation with at the expense of other passengers, in both Y & J cabins. Fine to have some banter, but when it means fawning over a handful of passengers and ignoring the rest that is not a good thing.
The other that is exceedingly difficult for anyone to overcome, is the cultural factors when it comes to service. It is interesting when flying on Emirates (which have probably the most multicultural crew out there) to see how the different nationalities serve and interact with passengers. Varies wildly.