Why does this spelling mistake bother me so much?

Not being a native English speaker, makes me less critical about other peoples spelling. However, there's one spelling mistake that just makes me cringe whenever I see it. Now, because I spend at least some of my internet time in forums, that means I see that word quite a bit.

The word is Your. What's that I hear you say? “Your” is not a misspelled word? Oh, but it is when it’s used instead of You’re. And the problem is that it seems like this mistake is starting to take roots – starting to pop all over the place. I just got this in my email:

 

I just hope our dictionaries will be smart enough to point this mistake out at some point.

I usually don’t like ranting about such inconsequential things, but I guess I have my pet peeves just like each of you have you’res.