You cannot blame the speculators, they are only trying to cash in on an opportunity. They do not (usually) cause a crisis, but they tend to make it worse.
The Greek, Spanish and Portuguese Economies are the most at risk at present which might give us some breathing space. They will not set their sights on betting against our currency only if they think our economy is strong and robust and we have a good plan for settling the deficit. Are you confident about we are in that situation? If there are any cracks, the speculators will be in.
Normally, a country in such dire straits as Greece would call in the IMF who would tell them how to run their economy to get it back on track. This would in practice be very humiliating in the Eurozone where the European Central Bank (ECB) runs things. Would the other 15 countries in the Eurozone have to follow the IMFs figures? So the ECB will not allow Greece (or Spain or Portugal or the others) to get the IMF involved and Greece will be re-financed from the EU.
We do not have that same insurance policy. If the speculators come (and they might not do) then we are one our own. So it might be a bit premature to scoff at Greece's plight.