Recently there has been a little debate on what is the difference between a normal us (no matter what path you have taken) and a satanic worshiper. Let it be said that it isn't from on this site but I still believe it is important to know the difference so we may better defend ourselves in case we walk into a debate like this. (P.S. this isn't about satanic people being evil or bad, just the difference.)
If you are Pagan than you may have heard of The Horned One. He is basically the father of Nature whereas Gaia is the mother of Nature. In fact, if you ever looked up a picture of him or read a description, than you may get a strong idea that he looks just like Satan from the Christian and Catholic religion (even if the bible doesn't say what Satan or Lucifer looks like "http://www.bcholmes.org/wicca/satan.html"). The reason why both sound the same is because way back then the Christian Church wanted more followers so they made one of their Gods sound like some scary person in their own religion. Again, I am not badmouthing anything or anyone, just a little history lesson. There is no connection of any of our religion to theirs. Yours or mine does not talk about their God or Satan and their bible does not have anything (with my limited research, brain knowledge, and misc resources) to do with ours. This does not include the mix religions of Christians/Catholics with ours (Meaning they believe in the bible but also believe in, lets say, Wiccan law).
With little to no connection that bridges that religion to any of ours, it means that we do not worship Satan but our own Gods and Goddesses. So if we see us as not worshipers of Satan, than who are? Simple, Satanists. I meet a few and even got to know them a bit. Some were lost to their own will of excitement while others were dead serious of their religion. They don't follow sinful actions or go out of their way to destroy things for no reason but for sin itself. Well that might be a bit off since everyone is different but the serious ones I have meet are like that.
Being a Satanist means that you believe in the bible and you are part of the Christian/Catholic religion. It sounds rough and harsh to them but that is true. They follow Satan because they desired to go against those people that keep telling them what they can and cannot do (is the most common reason). They can also have mix believes by believing in Satan and some of the wiccan Gods or even the Voodoo Snake God. Here is a better thing to understand, there is a light side and a dark side in the religion.
I lost my train of thought here, but I hope that this helps to clear up any confusion, if any.