There's an argument out there that the only reason breasts evolved into their current form was to mimic the allure of the ass once we began to walk more upright as a species, and thus boobs are just an inferior knockoff of the ass. But I say nay, NAY. If your appreciation is for the ass, then you should also appreciate the breasts for doing their breast to please you as much as their predecessor. Your appreciation for the breasts will not diminish your appreciation for the ass, nor would newer appreciation for the ass diminish your appreciation for the breasts. They can exist harmoniously, and perhaps that was exactly how the gods or nature intended it.
This has been an excessively serious sounding look into my thought processes on something that is pretty much insignificant. I apologize for any time you feel you wasted reading it. I don't apologize for that best/breast strikethrough joke though, so if that's your beef you can fight me over it.