Again, your answer leaves a lot of questions. If you are too shy to reveal the source of your angst, it's hard to provide any advice or help. Gas or pepper spray leaves a lot to be desired. Both can come back and incapacitate you as well as your aggressors. Gel is one answer, a taser is another. If you want to really cause someone to back off, go to your local boat dealer. There are air horns small enough to fit into a pocket. In a dark corner late at night one thing that nobody is expecting is a loud noise directed at them, coming out of nowhere. It will stop them in their tracks during which period you can hit them with the gel or tase them and then leave the area. Make sure you are out of the area before they have a chance to gather their wits recover from the Gel or taser.