What does Pook Kai mean?
Oh come on wiki has a page on this, since when did this turn into Yahoo answers? I've got a back log of questions waiting, but I'm bored and decide to answer which ever ones I fancy in whatever order I fancy. TCG hears this outside the Manchester Chinatown Bookies quite often after a big race. Men will come out tearing up their tickets and will curse pook kai!
Literally it means hit head on street ~ but its more complicated than that, i.e. its more like may you become bankrupt and either:
End up having to beg in such a manner. (absolute humiliation)
May you lose all your money, fall over in the street and be left there to rot since everybody who cared about you in your life has left you and you are all alone.
However given the context of Hong Kong where money is everything and having to beg is even more humiliating than death (you can't be embarrassed when you are dead). I prefer the bankruptcy meaning of things.
You can of course make it worse 死 仆街 adding si on the front.
Such an insult doesn't phase TCG though as most things flow over him and TCG generally doesn't give any body any reason to be called this either.