Sometimes the evil spirits can take the form of people you know. That's why you have to be careful
I.e. perhaps - don't blindly trust people, use your own judgement.
What's the difference between asking god for success for example and asking a spirit?
The spirit will take something from you in return, even though initially you seem to get what you want easily
I remember before I came to Indonesia I was pretty dismissive of people's beliefs in the supernatural. I still don't believe in a literal way like so many people seem to.
Yet there is something to what people say. Common sense couched in the supernatural.
Spirituality is a very human thing.