well OP,
I think that you, on some level, ARE doing it "on purpose." I DO NOT say that to accuse you of "intentionally deceiving" anyone, either. A contradiction it would seem, but in all reality, it is not paradoxical in nature, as "on purpose" can refer to anything formed by habitual practice over and over again. For example, when you stand up, are you "willing" your legs to pick you up "on purpose?" No. You're not. ANYMORE << THAT PART IS SO important to note: the usage of the word "anymore" because, there was a time, when you were a small child, a "toddler" (so aptly named), that you did have to consciously "put your feet down and stand up" so to speak. So, the difference I'm attempting to hint at is this: Are you just repeating a learned behavior (the "toddler effect"), or are you, in fact, INTENTIONALLY LYING to the people you're around? You, and ONLY you, can answer that honestly!!
-Tom