I've never really spoken to or come across the regular postman in person. I see him every now and again out of the living room window, but that's about it.
The postmen who deliver packages from Royal Mail on the other hand, I really do hate. They'll come around at 8/9am and knock so lightly that you'd have to be sitting in complete silence to hear them. Not only that, but they don't even knock a second time, they just leave that piece of paper that tells you that they've been 'round and to pick your parcel up from the local Royal Mail place. As if I'm going to stay up or get up early when I won't be able to hear the guy knock on my door anyway. You'd think they'd have common sense to knock louder when somebody's living in an upstairs flat. f*cking assholes.