I find it amusing how people use sarcarsm before giving a sincere response. Shooting a sarcarstic remark actually gives the other person an idea of your typical sarcarstic response and hence, he/she can generally identify how you'd reply sincerely. In some way, sarcarsm elevates the level of sincerity when you're giving genuine responses (when in fact, you don't really mean it altogether).
I think it's a pretty useful communication device especially when you don't feel like giving a frank answer. It's a little deceptive but I think it's a good way of staying away from offending someone ;) (Anyway, I don't really employ this method of communication much, this post is a product of observing other people)
