What irritates me the most is incorrect punctuation and capitalization. I make spelling errors occasionally (especially if I am posting from a smartphone), and tolerate them to some extent. What really detracts from fluid reading is if you have run-on sentences that contain incorrect capitalization. That’s what irks me the most.
Oh, by the way, I just wanted to share this from my first thread on the SDMB when I tried using voice recognition to post from a smartphone:
Although, I admit it wasn’t purely voice recognition. I did go back and tried to fix some errors that I found.