Just from my observation, the more people drink the less aware they become of others. They often become more noisy - even if its just a case of chatting more loudly, or laughing. In economy, they are more likely to knock something over, or simply allow their elbow or whatever to hang over into the aisle or into the other PAX's space. Add to this its the FA's that end up cleaning the toilets afterwards, I can imagine that serving alcohol can seem rather pointless.

I've noticed that PAX who should otherwise know better will happily boast in other forums here about how they got some kind of upgrade and were delighted to be able to "polish off a bottle of dom" or whatever. I can imagine the "just because its free" thing fuels the demand for booze and the FAs must get annoyed from time-to-time.

I sat next to a guy in Eva's premium economy class who told me how he always made a point of ordering as much beer as possible. 17 cans was his record for London to Bangkok. He only got 5 this time.

Finally, the first time I flew with Air France in C, the FA offered me some wine. He spoke to me in French and rapidly lost me. I said "I'm sorry, I don't really speak French". He then switched to English.

I asked "which wine would you recommend" to which he replied "they are all very good... I recommend you try them all". He came back with more glasses and put a little of each into each glass. Following my tasting, we concluded I should start with one, and then finish with another.

As he cleared the stuff away, he asked me if I enjoyed the wine. I said yes. He then replied "Sir you said before you don't really speak French. You know you really should - the wine tastes much better that way." It was a kind-of put down. But he got away with it - just.