This post is not some supernatural thing about witches and such. This post is about the probability of a curse working.
We all know that on some point we are all connected. That there is a common conscious we all belong to, or at least we are made from the same building blocks as anything around us.
Taking this thought for our foundation, I want to make an example that is overblown just to show the basic idea. What if 2000 people are wishing that you brake your leg? You probably will brake it. The curse basically is the same thing. Someone puts a curse on you, meaning they wish something bad happens with you. Usually one person cannot cause much harm with a curse, but there are people who can really put a lot of energy in the thought of you getting hurt, so they manage to influence in some part any bad happenings with you.
For example, there are parts in the world where orthodox priests still put curses on people for money. Also he can lift the curse for money.
The biggest problem with curses is that people believe in them. If you believe that curses work, they will affect you simply because of the placebo effect. If you think that curses are bullshit and still strange things happen with you, probably you caused some harm to someone and they really hate you for it.
So, if you feel cursed, just think about what bad things you did and go apologize or fix the problems you caused. It will lift any curse from you that you might have.