Why do women not say what they want or mean.

I have discovered over my past 5 and half years of marriage women don't mean what they say. Example: When you ask her what she wants for dinner and she says "I don't care", she real means what ever you want as long as it is what she want. The man will suggest something like pizza. She responds with, I don't know. That means no. Then the man suggest Applebee's, she says the same. Then the man suggest Olive Garden. She says OK if that is what you want.
When she said I don't care she really meant she would like to go to olive garden. Why must women be so complicated. Just tell me where you want to go. Please, I beg of you stop making men guess what you are trying to say we really don't care if you choose. If you want a point to be made, say it don't make us guess. It will save men and women allot of frustration.