A few years ago I went to the graveyard to visit my late godfather during the day. On the way out I noticed a woman walking on a parallel pathway. She had bright white clothes on.
So I walked, looked over to her and for a short moment my line of sight was blocked from a tree between us. After that moment she was just gone.
That being said, I didn't believe in ghosts and I still don't believe in them. There sure is a perfectly fine explanation. However, you can bet that I bolted from that graveyard.