i think most times you'd never see this side of the customs or immigration but sometimes, somehow innocently even when you follow the rules (maybe they just had bad day), these people can behave rather unruly. However, it is extremely prejudiced which is quite sad to see as if you look ang moh then no problems but if you look like you're from a poor country then they speak to you in a different tone.
i was behind this maid the last time, and immediately she was picked upon etc. because her english was poor, so think these officers have a LOONG way to go for services standards. the bomb words are just an excuse that allows them to screw you but overall, the service could seriously improve.
how welcoming to go to some countries where the immigration welcomes you with a smile and a welcome to singapore notion. oh... have you EVER heard that from immigration for those foreigners? (i'm Malaysian, technically foreigner).