I am sorry, too -- I have kind of a quick-draw on the sarcasm, so it tends to slip out sometimes on it's own. Also, since I am very direct in expressing myself, nearly 100% of the time I am read as MUCH more intense than I intend whatever I have written. I'm really quite harmless. Laugh away! I am not offended. I just mis-interpreted your laughter as pouncing upon my mistakes and was attempting to defend myself. I realize that sarcasm is definitely not the way to go when the other person cannot see the twinkle in one's eye when it is "said" in writing.
We are perfectly cool.
No need to worry or make amends.