Oh, yes, that was a detail I had forgot about.
While Hpa318 just stated what happened to him and his mom and nothing else, you wrote I-don't-know-what about superior or not. I can't even imagine from any word of him say anything like this.
Yes, they are very very undisciplinated. And the problem is not (only) of the passengers: the problem starts in the F/As themselves. I've flown in an airplane FULL of greeks (an organized group of 75 people + the occasionals) in a 100 seater of Iberia, and NOBODY was smoking. (although they tried to. But the F/As stopped them immediately and nobody dared again). It is the same in the taxiway after the landing. The aircraft is still on the runway and they start to stand up, pick their hand luggage and so. I have flown for several years between BCN and ATH in different companies, and I have seen that when they are in IB's or in AZ's or in KM's or in LH's airplanes they tend to do the same, but F/As do not allow them, while on board OA nobody cares...
I would not say anything impossible, but I guess that one hour difference in a trip that shouldn't exceed about 3hrs30 is a little bit too much... I do not know how much does a LHR-or-LGW-to-ATH flight lasts, but let's say that if it takes 3h30 at 900 kms/h, one more hour, meaning 4hrs30, would mean that the plane is flying at... 600 kms/h!!!. Even in a mUUUch longer one, let's say about 5 hours at 900 kms/h, would be 750 kms/h if flown in 6 hours instead. Some figures do not match...
Of course I am talking about calm wind and true indicated airspeed. If we translate it into ground speed, it could be possible if there were a very strong wind against the plane. But this has lees to do with the bad luck than with the airplane type itself. My experience was ATH-MAD in 4hrs10, when the usual is 3hrs10. Yes: one hour more. But it was due to strong wind. In both cases the aircraft was the same: OAL A300-B4
YES IT IS TRUE:
Olympic Airways has a smoker's policy, meaning that approximately 1/3rd of the back of the airplane are smokers' seats.
It is maybe true that this is not enough since the smoking part of the Greek population is not 33,333%, but some closer to 99,999%... (My ex-wife among them) (She is greek)
And it is true that I have never even tried one only cigarette.
Finally, it is also true that my ex-wife complained about having had to fly eight hours (BCN-ATL, in Delta) without smoking.
But it is also true that a greek friend of hers that had flown ATH-JFK in an OAL-B747 answered that she, being a smoker, would have preferred to fly 11 hrs to JFK in a non-smoking flight rather than in an OA flight, because of the "smoking jungle's law" imperating (especially on board long haul) Olympic flights.
But, for the rest, and if you do not mind too much about smoke, I assure you that you are going to enjoy both the airplane and the service warmth.