I also still have trouble with affect/effect; I can't tell you how often I've visited Google about those words at work to be sure I'm using the correct one. I also have sensory trouble with my fingers, so it is easy for me to make typing errors.
Since I am confessing some of my writing weaknesses, I will tell you that I am not a great speller, either. I do use spell checker when typing at work or creating important letters at home, but I don't always do so on message boards. I also tend to use long sentences and a lot of commas.
I try not to be judgmental about such issues on the message boards since I am far from perfect, but I will admit that phrases like "I seen it at the store..." do sometimes seem like fingernails on a chalkboard.
Edited to add: Sorry Eeyores Butterfly - I didn't see your "nails on a chalkboard" statement until after I had posted!