I love this thread. All of the consistent misspellers probably don't know what we're talking about, thinking, "I don't know what their talking about."
Seriously, there are enough intelligent people in the world to catch these stupid mistakes. As an intelligent, English-competent patient, I would hope my physician would be smart enough to write an intelligible letter to me:
Dear Mr. Jones,
I know ur having a hard time with this cancer. Your going to make it through allright, 'cuz I'm ur dr and I'll be able to give you advise. This new drug were trying is better then the old one. Its shown to be very affective in alot of trials. You "must" not loose hope. Good luck,
You're dr.