The reason is simple - you can lay on the innuendo and hint at things in just the right way - she can see it and like it and go with it, or she can see it, not like it, call you out on it, and you can backpedal and say you didn't mean it like that - and she doesn't have a reason to doubt that because the subtle levels present in vocal communication (inflection, etc.) are totally absent. But, of course, there's still the chance that she'll completely miss the point. Example foregone because she may or may not have seen me reading this forum once.
And relying on hidden meaning is bad when overused. So go talk to the girl, you pansies.
And relying on hidden meaning is bad when overused. So go talk to the girl, you pansies.