Future of EUR is been challenged by Greece economic tension, currently Greece is standing at edge of cliff, as they themselves want to jump down, as the default will not hurt much as compared to EUR itself and other European countries.
Currently IMF, EUR zone nations and Greece itself having a hard time, each one is considered as a player and has it own strategies and payoff (game theory by late Great John Nash). Greece is playing a hard ball game and testing the nerves of other players.
Greece are happy standing on edge, forcing other members to come to edge, and they have also come to stop Greece from jumping, Greece has to be bailed out to keep EUR concept true, if Greece falls out the whole EUR currency is going to get ripped off and each nation forced to take back it own individual currency.
Germany and other countries who are against giving Greece more time, have already shielded themselves from the negative outcome.
So the next coming days can actually decide the faith of EUR as many of them don't want to take blackmailing from Greece.
If they just want to save EUR, they have to bail out Greece from financial shortcoming and write off loans.
So extremes is not possible, as all players are rational and instead out each one getting ripped off, will come and save Greece.