What annoys me is people who refuse to acknowledge that posties are generally quite busy people and that genuine mistakes can happen!
A few months ago I had a letter delivered (a replacement bank card) that had been addressed correctly, but it had inadvertently been delivered to number 3 instead of number 4. The envelope had been marked "NOT NUMBER 3" and deposited in the post box for re-delivery. While the fault was either with the person who sorted the post or with the postie who failed to notice, my anger was, quite rightly, with the resident of number 3 who would have had to walk further to get to the postbox than the distance from her front door to mine!
This is the same person that nearly threw a tantrum on my doorstep because I'd taken in a parcel while she was out because apparently she'd instructed the company not to deliver to a neighbour.
At Christmas I sometimes receive cards intended for number 14, but have been addressed to me in error. I'll either walk over and post them through the correct door right away or, if I'm busy, I'll leave them by the door and deliver them the next time I'm out.