Double Spaces

Of all my numerous pet peeves, one of the smaller ones are those who use double spaces between sentences when using proportional fonts. When using a fixed-width font, adding two spaces after the period is correct. But otherwise, a single space suffices and two spaces is too much. It is one of those "a computer is not a typewriter" things. I particularly do not like when I see the use of double spaces by people who should know better.

Several years ago, I had to train myself out of the use of double spaces. Now, I forget to use them when appropriate. I almost always use plain text for email (html in email is, if not actually evil, mostly pointless), yet I only use a single space. So, I am use my lack of double spaces is someone else's pet peeve (assuming anyone even notices).