I think sometimes guys take the ****y and funny too far, me included.
One time I was out with this girl I really liked, and instead of being real with her, I just stayed ****y and funny like I didn't give a damn.
I think you've made an astute observation. The whole ****y and funny thing can often come off as incredibly lame, and fake. I know David DeAngelo pushes this C&F thing to the hilt, but can you honestly tell me you don't think he comes across as a douchebag?
C&F strikes me as something that can work if it is congruent with your personality, or as something that can improve your game if you are very young and/or socially retarded to begin with. Otherwise, it is far better to "be real" as you say. That is the better strategy.
I take the mindset that women like to be teased, and I like to tease them. Sometimes this teasing might take the form of what could be considered a ****y and/or funny remark. If it does, fine, if it doesn't, I could care less.