Gitana1: Perfectly stated.
I've been approached too many times--males deliberately walking in front of me, cocky-looking, staring. My usual response is "**** off".
I was approached by a homeless person not long ago, asking for the time. When I refused to give it to him, he got hostile. My verbal response would have made ears singe.
I've started carrying a stun gun and pepper spray. I may invest in a portable knife like the one you wear when jogging.
We can't afford to be victims. Ever.
I wear mirrored sunglasses, which can project the idea that I'm not approachable. It helps.
And don't be afraid to use your phone to photograph someone who looks intimidating as they approach you. Keep it set to "emergency" mode.