Japan is all about utilization, not having fun
in squeezing people on trains.
Here, I don't know what is it, but I am not commenting as I do
not take the train often.
I guess Japan's situation is different - their population and
urbanisation levels are much higher than Singapore's. I don't know
how frequent their trains are, so I can't comment much, but I
assume that they have tried running more trains to alleviate the
crowd; no-one there probably wants this kind of situation.
As for Singapore, I sometimes wonder if SMRT is delibrately
running less trains so that this kind of situation can happen in
our city eventually - 5 minutes is definitely unacceptable for the
crowds I witnessed.