Such a simple question, so difficult to answer without sounding like the naff carrier adverts of the 1980s.
Firstly, in 37 years of zooming around, I have had so few bad experiences that I find 95% of service must be OK or Good or Brilliant. Which leaves me little constructive to say. Or it might just mean that I have very low standards.
I would like to know that FAs could stop silly pax from wandering around the cabin when we are already well into the let-down and similar saftey issues. But I know that the pax will think that the world has ganged up on them and that YOU are the personification of all that is wrong!!!
Thinking about this some more, the problem is to find good Pax!! Mostly what makes a good FA appear bad is a persistently stoopid pax!
The best ever? Last year, I was in C on LH long haul (MUC ~ JNB A340) I am one of those that stays up late reading and writing, so the personal light is very important. Mine did not work.
The attendent struggled with it to get the fitting out and change the bulb but it was jammed and they gave up. I tried. The flight was full and the only other seat in the centre and I am a window junkie! Then another attendent came over and struggled away at trying to get this wretched little fitting out. All of us bemoaned that none of us had out Leathermen tools, as this were in the hold! After 20 minutes of struggle from all of us, I thanked the FA and CSD and told them to forget it. BUT the FA continued until he got the fitting out and we discovered a lose connection, which he fixed. So, I had told him not to bother any more - but he did bother!
