The things that piss me off the most aren't really spelling errors...it's more the spelling errors of things like "their" versus "there" or "they're" and "your" versus "you're." A friend of mine consistantly is typing "your" instead of "you're" and I always correct him. He always gets pissed off at me. He told me the other day he's not being ignorant, he's being lazy. What's the freaking difference of adding two more characters to the freaking word?! It takes a half a second longer.
Maybe I'm just annoyed easily because I can type fast and therefore properly spelling and punctuating isn't a problem for me time wise. Some people use the "hunt and peck" method and it takes them forever to type. But even still--typing like a teeny makes you seem...well, like an illiterate teeny!
Another thing that bothers me is people who use numbers instead of "to" or "for." A perfect example of a sentence I hate is: "u got 2 go 2 the store 4 sum apples". No capitalization (which I can deal with), the use of "u" instead of "you" and the numbers 2 and 4 in place of "to" and "for." Also, instead of adding an extra letter to some, they just type "sum," which has an all together completely different meaning than what they intended it to be.
I also hate people who type run-on sentences and don't use commas and add "and" every other word to link their thoughts and and and....hehe. I realize I'm not funny.
Wow, that was long. All I wanted to do was say hello.