how should you deal with people that act familiar with you, when you don't know them

this really irritates me when i'm out in public, people behaving too familiar with me when i don't know them and are a stranger to them....like people looking at you in a familiar way...it really pisses me off!!

i'm just a private person who likes to mind my own business and even, go unnoticed if i can...so how can i deal with this shit? i take offence very easily.