I have been living in Greece for 35 years, 25 of which as a self employed professional. I have heard a lot about bribery but never been asked for a bribe. When building my house it was pointed out that the town planning license could be expedited if a bribe was paid but no one could point out the official to bribe. The license was issued without any bribe or gift etc.
Considering that Greeks are prone to dramatics and also that they are lousy tippers, I do not see them pulling any money out of their pocket for a bribe.
My uncle, who's friggin Eparxos of Larnaca has basically been disowned from immediate and extended family for that exact reason. No Meson, No fakelakia to Nobody! Everything by the book. Alot of disappointed people, trust me I know first hand. lol