Our day flight out to Vancouver was OK but our return flight was very uncomfortable. We left Vancouver at approx. 2 o'clock in the afternoon in Economy class. The gentleman in front of my husband fully reclined his seat which greatly restricted my husband's space and movement (perhaps there should be a limit on how far back one can recline without obstructing the person behind?). The weather was excellent and, of course, bright sunshine at 36,000+ feet. We were to fly in sunlight all the way to Frankfurt due to passing through different time zones but, body-clock wise, during our Canadian time night hours, and would have expected people to wish to sleep at, say, 10 p.m. However, at 4 p.m. the crew told all passengers to lower the window shutters, plunging the whole plane into darkness apart from the individual spotlights. When we queried this (we don't normally go to bed at 4 p.m.!) we were told that some passengers wanted to sleep. Replying that we ourselves didn't want to sleep at 4 p.m. and there were probably others who didn't, we were told that we'd have to face complaints from other passengers if we kept the shutters open. The crew were "politely" insistent and so we complied. The result was a flight of, by then, 9 hours out of a total of 11, in what I can only describe as a "flying coffin" - dark and claustrophobic. The transfer flight down to Athens was a "normal" one but I'm afraid Lufthansa have lost our custom. My husband has contacted the airline, asking why crew said that shutters should be closed at 4 p.m. in the afternoon, rather than the normal average bedtime of, say, 10 p.m. We await their reply.