After doing some research, Greasy Lake is not an actual place, but a "spin-off" of a Bruce Springsteen song. The story was written during the Punk Era in the 1980's, and the author merely replicated the styles retro to the mid 1960's. No matter what era we live in, however, there is always a "Greasy Lake" anywhere on Earth.
That being said, I refer to a place called "Inspiration Point". The only inspiration created from going somewhere such as this is how much fog will collect on the windows. My point is simple. There are certain places that certain people go to do certain things. I'd be willing to bet that the bad boys in the story wouldn't be so bad if they were at Grandma's house, or at church. The name in itself, "Greasy Lake", releases the essence of, for lack of a better term, badness.
The filth, the muck, the litter; all bad. It was once called "Wakan", which was a reference to the clarity of the waters, according to the Indians. That's quite a contrast to the same place at the time in which the story takes place.
In conclusion, the characters in the story that were supposed to be bad, found out the hard way that there's always someone worse. The setting was a major influence on their behavior, at least until that fateful night. I daresay they probably weren't so bad after that, and may not have even gone to Greasy Lake again. It's one thing to be bad, but another to be "scared straight".