The USSR had a high cost in the military and suffered from economic stagnation. Unable to grow enough wheat they had to buy from the USA to feed their people.
Greece didn't raise taxes enough to cover their debts from social programs. As their economy grew worse the cost of health insurance rose and costed more.
A lot of European nations can afford socialist programs because they don't spend a lot on their military due to the USA protecting the European coasts after WW2.
Canada also does not spend a lot on their military due to a partnership with the USA to protect their coasts as well. So they have more money for socialist programs.