1) The polarisation of Hellenic politics in the 70s (extreme Left Vs Extreme Right), culminating in the development of EOKA which, in its second incarnation as EOKA B, performed the role of a nasty murderous terror outfit which backed the laughable, pathetic tin-pot dictators that formed the Junta of Greece.
2) The backwards, ill-educated, static, peasanty, villagey, stupid population of Cyprus, post 50s, which found itself in the position of having to run its own affairs after centuries of tilling the land and seeing foreign powers run shit for them. All the while, technology and modern practices began to set a pace, while emphasis on schooling and education remained low.
The two combined helped to ferment and develop a political situation that led to the Cyprus problem. It's all very well finding a nice easy scapegoat for things (Any one of the bigger powers at play. If you're Piratis, it's ALL the UK's fault.) But when it really boils down to it, the Cypriots, and I mean the GCs really, fucked it all up.
And I say this as a half GC.