I am an Indian, dress neatly- I feel people comment on me in bus and train, positive of course?

I feel people comment on me while traveling and at Uni- in Sydney. Does this happen or my psychological problem! They are positive comments, I am lucky. I wonder what would it be if it is negative whispers. I asked my chinese friend my problem- he says its better than commenting in your absence, and also says that they are compliments. But I feel like uneasy. I appreciate that them commenting good on a black shows their nice and open mentality, but I am a shy guy and do not know how to respond. How shall I respond under such situation. I worked many years in industry under tough conditions, so my personality reflects confidence and toughness, which is unique to typical Indians. I feel the same at uni while going by bus as those teenagers commenting on me- positive again and thank god. I love communicating with those beautiful girls but do not know how to. Can any one suggest me please?