I attribute some amount of that perception to wierd affectations of mine. For example, I prefer "behaviour" to "behavior" and "hilite" to "hilight"; I also enjoy using semi-colons (and overusing parenthetical comments). But mostly I'd guess its because I never use a spell checker :)
I did use the spell checker provided by my blogging tool early on, but I stopped as soon as I noticed that "blogging" wasn't in its dictionary. It suggested I use the term "flogging" instead.
Perhaps it was trying to tell me something.
In any case, I suppose I could use a word processor, or simply train the aformentioned spell checker with the words that I tend to use.
Honestly though, when it comes to flogging, I'm OK with a being a tad sloppy. My wife calls it "laziness"; I tend to think of it as "economy of motion".