First, I hope I haven't embarrassed or put off any other girl by discussing this topic. If I have, I am sorry, it is not my intention to embarrass (and please refrain from reading this post further).
I have known man to be fascinated with mammaries since ancient times. I have read books from Indian literature which provide tasteful, graphic anatomical descriptions. I won't go as far as even the KamaSutra, just take kaamathu paal in Thirukkural. And the works of sculptors, painters, poets, writers exhibit SUCH rasanai (skill of aesthetic appreciation)
I hate the stigma our society attaches to human anatomy. Breasts are just another part of the body. I think looking at breasts is fine unless it intrudes into a woman's privacy (like hidden webcams, camera phones). I know I can't stop anyone from looking at my sister or wife or mother with "the wrong eye", unless I keep them locked in my house.
I can maintain perfect eye contact with a girl because breasts don't distract me. They're nice to look at (just like eyes, hair, smile...), but when I'm talking to my mother or sister or co-worker or friend, they are not the object of my attention (just like eyes, hair, smile, are not), because relationships (personal or official) are not about the body but the mind! I am what I am today mainly due to women - my mom, my girlfriend, my sisters, my penpals.
I think the sight of a mother feeding her baby depicts the purest form of worldly love. Breasts are the only organs that can depict both purity and titillation. That's why they are so special!
From childhood, we are taught that talking about anatomy is taboo. This increases curiosity. And we have no proper method of sexual education. Which means information is mostly obtained through improper means, which is often factually improper. Though it is natural to be attracted to the physicality of the opposite sex, someone who talks openly about admiring breasts "shocks" society. I don't see vulgarity in the eye if it is not in the mind.
My friend used to say, "Azhaga rasikkardhu thappille. Adha adayanum-nnu nenaikkardhu dhaan thappu"(No harm in enjoying beauty. Harm lies in thinking of subjugating/possessing/attaining it).
The reason I write so much here is because my sister means the world to me. I value her words because they are always out of concern for me. Till now, I don't believe I'm on the wrong path! But her words make me want to think again...