Going to sleep tonight.

Ghosts.
The question is not whether they exist or not, but rather if your sanity is ready to make them part of your reality.

Sightings of ghosts imply photons.  That implies the use of a camera to capture these sightings.  Zing!  One big, fact, fucking lack of evidence later, and we conclude that ghosts are about as real as fucking Gilgamesh.  Practical logic wins the day again!  Bullshit sinks, 'cuz a sensible man thinks.