A couple of days ago I was going to leave my CV in a couple of places that are hiring: as I walked down the street a guy suddenly started walking a few feet from me, clearly following my path. First he tried the usual "hello", then he moved to "hello, beautiful" - I ignored him and didn't make eye contact.
After another couple of attempts to engage, I decided to shut him down: I turned to him and said in my frostiest tone, "Do I know you?"
Me: (dryly) Exactly.
He stopped following me and slinked away. On my walk back, I kept an eye out for green t-shirts, crossed to the other side of the street and took a bus home.
I'm pretty proud of myself, especially for not answering to the first "hello" - that always gets me. My frosty tone probably needs work, but I'm glad it worked this time. I'm not even feeling guilty for being "rude"!