I’ve just finished delivering 150 leaflets for our local residents’ association, inviting people to our next meeting. A simple enough task, but not without its hazards – and their accompanying insights.

What you realise is that the letterbox is the only point at which someone can intrude, unasked, into another person’s home. And, as such, it takes on an interesting psychological importance. One can’t help thinking that every letterbox reflects the personality of its owner.

There are the wide and generous ones, for example, that open easily, positively welcoming your missive to float on to the doormat. Their owners are clearly lovely people – or perhaps just the gullible type who take in and are taken in by everything.

Some residents, though, have equipped themselves with tiny, doll-sized flaps that force you to fold even a modest leaflet in half. These remind me of the pursed-up mouths of the disapproving spinsters you expect to find in a Victorian novel but not in 21st century West London.

Worse still, letterboxes both wide and narrow may have a defensive screen of bristles around their inner side, which traps your offering and turns it into something resembling a reluctant child’s homework before it ever hits the mat. The bristles are, I think, meant to stop draughts. Draughts? Through a letterbox? Just how sensitive can you get?

But of course every post person’s deepest hatred is reserved for the kind of letterbox that betrays its owner as not merely judgemental or over-sensitive but as a paranoid sadist. I am speaking of the dread spring-loaded letterbox. The springs of these devices are nicely adjusted to trap the fingers; their flap is honed to an edge that will remove a layer of skin thick enough to be painful but thin enough to prevent you calling your lawyer. Someone with a letterbox like this clearly hates the world and exacts a price when it tries to communicate.

So what kind of letterbox do you have? Have I made you feel bad about yourself? On enraged with me? Perhaps I have just sent you scurrying off to the hardware shop for the sort of letterbox that says what a great human being you really are.