ATH McDonalds
I can't believe that I'm posting this, but there's a little oasis of relative (note relative!) tranquility at Eleftherios Venizelos airport in Athens.
I've used it a couple of times now, when catching an early domestic flight where breakfast isn't served and also where I've left the hotel too early to eat there.
The Golden Arches are located in the duty free area, above the departures level, towards the B pier, but before boarding pass inspection for the pier, so anyone can go there.
Whereas the coffee bars downstairs are heaving, the McDs is relatively quiet and a Big Breakfast is EUR 4.42.
After that, one can relax to either of the Priority Pass lounges (Olympic's own), which are well appointed.