What's the cheapest First fare London to East coast of US? Probably more than £3k? I would expect that peoples level of expectation is dependant on the price they have / would have to pay. It is also no doubt dependent on the amount of money one has to burn.

When I was an 8 year old child; had I had to pay £10 for something I would have expected a great deal in return. A Ferro Roche Easter egg for example would have not been luxury enough knowing that I could have spend it on 100 Cadbury Fredo bars for 10p each.

Similarly, when I was 17 and went to SFO (2001); I would never have considered paying more than £250 return for the the flight. So the £160 I paid seemed acceptable but still expensive.

Right now, if I were spend £3k on a trip to east coast of US on the flight alone I would expect a very high level of service within the bounds of what is practical. If I am lucky enough to be earning £750k in 10 years; I may not expect the level of service I expect now as I may see it as pocket money.

While there is a level of expectation, you need to make these things work for you. One can have a perfectly pleasant experience in Y on a 5/6 hour day flight (9+ hours is pushing it a bit) just as you can have a rather unpleasant experience in J / F if the expectation is not at the right level.

So for me:
WT: you sure know you are travelling and will be afforded the level of service you get when driving your own car
WT+: less like you are travelling but more like sitting in theatre for a long play or travelling with someone else driving
J: the travel should have a minimal impact on you (but that is not guaranteed)
F: a level of luxury compared to your own sitting room (never done it but I would expect not to feel like I had been bolt upright for hours and fed hospital food in a ready meal container )