You are so right, Skarpi. "Breasts" is the one word that gives these bodily features the respect their owners deserve. The other words are either somewhat crude or just plain silly-sounding.   "Boob", for instance, used to be a common English term meaning "stupid person", "dummy" or "fool". Then a lot of people started using it for breasts instead...I have no idea why they did that. It sounds completely idiotic to me to say "boobs" when one means "breasts". It is, however, a symmetrical word which geometrically suggests a similar structure...

B + O .... O + B

Maybe that has something to do with it in a subliminal way? Even the capital letter "B" by itself looks like a sort of visual representation of a pair of breasts, after all.

"Mammaries" is a sort of technical or scientific term, suggesting "the mother". Breasts are referred to in English language biology as "mammary glands", meaning that they serve the purpose of providing a mother's milk to infants.

All of this may have been lost on Hugh Hefner, I suppose... ;-)