I too don't understand the whole picture about Turkey-Greece conflict maybe
@Sinan @xenon54 @Cabatli_53 can tell us the story.
I think i dont need to repeat what happened in middle ages since you probably know it but let me explain the recent history.
Turkey and Greece have two major disputes, one is Cyprus and the other is the territorial waters in Aegean.
Greece wanted to annext Cyprus back in 70's and made a coup there, then started to massacre Turkish minority on the Island, Turkey as one of the three
guarantor mights of the Island intervened and occupied the Turkish populated north in 1974, after that no agreement could be reached with Greece and North Cyprus became de-facto independent.
And about Aegean, Greece wants Turkey to accept the International 12 miles rule which Turkey refuses because Greece could cut off the connection between Black sea and Mediterranian for Turkey, Turkey on the other hand wants a 6 mile rule which would be a more fair share of international waters in this case.
Current 6 nmi.
The 12 nmi rule which Greece wants.
So its pretty obvious that Turkey is not gonna accept the 12 nmi rule.
There are also minor disputes such as some small islands and the overall situation is also quite complex but all in all thats it.