What are the scariest horror movies on shudder?

I bought the shudder app because I love horror movies. The problem is the fact that there are so many to choose from. I really need help finding something that is not cheesy, and will actually scare me. If you do not have the shudder app, then tell me what is the movie that scared you the most. A movie that haunts you to this day. That is what I want to watch.