I thought I was an atheist until some things happened that made me question that too.
I think everything has a reasonable explanation. I was sitting at the piano only last night and i could very clearly hear someone running up and down the stairs. It wasn't my daughter because she was fast asleep in bed, and she's only 3 so cant run up and down them. As a JW i would have been convinced it was demons. Turns out it was her next door doing her exercises.
Being an atheist for me is living without fear of anything supernatural. If something supernatural does happen, i'd be curious to figure it out using science and mathematics. Not faith. Imagine if someone could prove with science and mathematics that they can talk to the dead. That'd be the greatest scientific discovery ever. We could use it to solve crimes, answer questions and advance humanity. But no... "mediums" dont do that. They just charge you £70 to tell you they're getting the name "John" or "Joe" or "Jodie?".