What you all seem to have overlooked is this:

The woman's breast is a sensitive part of her body. Yes, she wants it to be beautiful, but due to social influences and other such environmental factors, the breast is considered a personal area. To illustrate this, I'll use this point:

If I compliment a woman's face, eyes, hair, legs, belly etc, she will appreciate it. If I compliment her breasts she'll give me a slap.

To me, this is social conditioning, or maybe just over generalization, but it doesn't seem right to me.

Why is it wrong to compliment a woman's breasts?