I've always been interested in grave markers and the stories they tell. One day, my not-then wife and I were in one and I had been going around to look at the stones.
She went along but sort of hung back, too, until she said,
" We need to get out of here. There is an angry spirit here and he doesn't like our presence. I can't stay."
She went on to describe him, his period and even told his name - which was on one of the stones I had seen. The dates matched her impression of him. Most importantly, she had not been to that part of the yard... she could not have read that stone.
I did not know before that moment that she was deeply sensitive. That's when I learned about guardians. According to her, they are in most graveyards. I've since dropped my fascination with tsuch places.