I think so much depends on where you live.
The Postman at my parents place in Hertfordshire they know on first name terms, if they are out he will sign for something and hide it in a good spot, they give him a Xmas gift, and my Mum even gave him an old set of Golf Clubs a couple of weeks ago.
In Central London it's very different though.
I find with deliveries, most of the time, they don't bother bringing a package during weekdays, as they assume people are at work, so just leave cards. I've twice now had the postman in the block of flats I live in, ring the intercom buzzer, I've answered to him, told him I will be down, let him in, then when I get there a couple of minutes later, he has just left a card and f-offed! Rubbish.