Why do we capitalize I?

[Leanne]

I like I. I only occasionally use i, to indicate that the individual is not terribly important or has been subverted for some reason... and I find I don't really care what other languages use for their personal pronouns, simply that English has a convention (and if it's been in use for 800 years or more, it's a fairly well established convention) that I'm perfectly content to follow. If other people eschew the I, I don't particularly mind, but in my poetry I will always be distinct from i for the simple reason that I never make grammatical errors unless they're intentional (or I'm really not paying attention).