I didn't learn how to have a normal conversation until I was about 25. I'm pretty good at it now, but sarcasm will always be my first language.
I sometimes forget how sarcastic I am until I give someone a compliment and they say something like, "Screw you, jerk!" Apparently I don't do sincerity very well.
Still, I keep trying, in an effort to make something of my emotionally stunted personality. The other day I said to my wife, in an effort to express my admiration for her, "I don't think there's anyone quite like you." She said,"Hmm. I'm not sure if that's good or bad." And I responded with firm conviction, "Oh, it's good."
I think I'm going to stick with sarcasm.
By the way, I made the "motivational poster" at http://diy.despair.com/motivator.php.]]>