I don't often sad click, and like sal I will give random cc's when Im in a good mood. I only sad click someone when they're being a complete dick or being unnecesarily aggressive or something, never if they only have a contrasting opinion to me.
I think I have sad clicked you in the past bigragu, not certain if it was you but someone with a similar sounding name was being aggressive and giving directions to his gym to some other poster.