This is one of my Dad's experiences and he's given permission for me to share them.
If you ever go to a country with Chinese traditions and practices, you would not be surprised to see the locals burning incense paper (so called hell paper money). These are burned for a variety of reasons but mostly for the sake of our departed family or for rituals to pay homage to the multitude of Chinese deities. (for more details, please wiki it)
Anyway, my dad has always been a Buddhist and believer but in his youthful indiscretion, he once did something stupid. He was walking along the pathway during the 7th lunar month (which for Chinese, means the ghost festival month where the gates of hell are opened and which the living burns incense and other offerings to the spirits) and he chanced upon a pile of ashes from the offerings. Even a child would know to step aside and not purposely disrupt the offerings or ashes as a sign of respect. However, my dad went and kicked the pile of ashes (the ashes had been there for a while and was cold with nothing sharp inside it). With that misdeed done, my dad went home and forgot about it.
That night, out of the blue, he felt an intense burning sensation on his right foot and it started swelling. The entire night he couldn't rest as his foot swelled to nearly twice its original size and the burning sensation continued throughout the night.
He then became sick for 3 days with consistent fever and the doctor couldn't tell what was wrong with him.
To date, he believes that was a little lesson for him by whatever spirit he annoyed.
What do you guys think?