When you order Vietnamese coffee at Pho 79, the waiter warns you that it's strong. When he brings it to the table, he warns you again that the house makes it powerful, and to be careful. And after waiting for the peaceful drip-drip-drip of the tin filter to finish and the hot coffee to bleed down through the ice to the layer of sweetened, condensed milk on the bottom of the glass, you taste it and know that the waiter had only your best interests in mind. This stuff is like drinking sweet, coffee-flavored crack: It's addictive, it's cheap, and one glass will pin your eyelids back to the top of your head for twelve hours. So take your waiter's advice and be careful: This stuff ain't for amateurs.