nothing
nobody will look to bitcoin unless the dollar shows weakness
and even then they will look at euro, or some other fiat, i don't remember the strongest after euro, so bitcoin will not be their first choice unless the whole centralized economy collapse, and surely will not happen overnight will the Grexit
also if someone really think that a poor country like Greek with all the problems that they have about their economy, will start to buy bitcoin and to rise the price to permit that at random strangers or early adopters to dump it afterward, you are only fool yourself