You might be a quite person and that is why people would like to harass you. You need to stand for yourself and fight for your rights by not doing what you think you are not supposed to. People will respect you if you know what you want and not what others want from you.
The fact is over the years I've notice people are generally more and more impolite. I'm old enough to actually remember manners. Don't misunderstand me, of course this doesn't Apply to everyone, but it is one if those changes in our society that is really sad.
I find if you "smile" more, people are more willing to smile back or be slightly nicer. Are they rude in everyday situations? People you've known for a long time,or strangers? Sometimes people read your face, and act accordingly.