The idea of ghosts raises lots of human eyebrows. People will often fervently believe in such things or, be convinced they do not exist. Each person has a reason for their belief systems. Not everyone is prepared to explore reasons for their beliefs.
Let's say not believing is grounded in fear and doubt about uncertainty. Human beings will even deny what they supposedly perceive with their own senses. This happens because those people are not ready to believe, or to open up to unexplained experiences.
If you believe in the supernatural, it is possible you have had some unexplained experience and this is how you understand it. You may feel love and positive energy. Your inner knowing may also help you connect to energy vibrations that other people do not choose to have. What you believe, you consciously accept and embrace as truth.
I have a friend who shared a story about his visit to Bhutan. This is a very spiritual country I look forward to visiting. In any case, he rented a four wheel drive and took a guide with him into a remote area. My friend got out of the vehicle to gaze at the breath-taking scenery and to meditate amidst nature.
Suddenly, as if from nowhere, an older woman appeared in native dress. She spoke in a dialect my friend's guide did not understand. Now, the two men were many miles away from any village. They were amidst steep mountains and rugged terrain. Nonethless, the peaceful woman smiled continuously, bowed her head with a prayer gesture and seemed to walk by them. When they turned, she was gone. They sensed she was spirit energy.