Originally Posted by Pascoe

I am incredibly polite on flights. To other pax, ground staff, and especially to cabin crew. I have found over the years it has payed absolute dividends, whether that be in generous wine pours, extra service above what I'd expect in a given cabin, or even eg cockpit visits.

Plus it's just a nicer way to behave. If I am going to spend 12h in close proximity to people I'd much rather get on with them, at least as an opening gambit.