I'm thinking of following the teens around the store because they are black.
Why would you follow them?
They look so scary and intimidating and I'm afraid.
If you're afraid then leave them alone. I guarantee if they catch you following them and find out why, you're in for some trouble.
I bought a knife from the closest hardware store and I'm going to use it against them and intimidate them to leave me alone.
Please don't follow them and you say you have a knife. If anything bad happens you have no self defense this is all premeditated. Please mind your own business.