There you go boss!
See Grice's classic paper "Logic and Conversation" for the general framework employed by my use of the word "true."
When you speak with a sarcastic voice you are flouting the maxim of manner ("avoid obscurity of expression"). When you flout a conversational maxim, and you are assumed to be a cooperative conversation partner, it is assumed that you are trying to communicate something other than the literal meaning of your words in an indirect way.
Of course, this is the wrong inference, but unless people knew this habit of yours they couldn't help but making it.
In such a case you are taking advantage of the fact that the meaning that you cause people to falsely believe is deniable, so you are being deceptive. If on the other hand you are with your friends who know this habit of yours, and they are not deceived, then it is just that your circle has a rather ornate and perhaps exclusive way of calculating conversational implicatures.