Men are too often guilty of assuming that "hello" means "I want to have sex with you" Women think that because that is more often than not what it really means
You do realize that most people flirt for a reason, don't you?<br />
Unless it's a friend and they know it's just a bit of fun it really is unfair to think someone won't assume you're hitting on them if you're flirting. <br />
Personally, I'm oblivious and don't notice when someone's hitting on me until they tell me in plain speak, but considering that we're raised, trained and expected to follow largely non-verbal cues to direct communication giving people mixed signals like that and then criticizing them for not getting it is just cruel. The other party is not psychic.
because we're a sex-driven species