Just sit down for a drink with one of them and ask for yourself.
Most are fairly private about their taste for blood for fear of getting confronted by people with wooden stakes, garlic, a silver bullet, or fire.
The largest gravesite for vampires was in Perperikon, Bulgaria.
Other causes included having a cat jump across one's grave, eating meat from a sheep killed by a wolf, and being cursed.
In southern Russia, people who were known to talk to themselves were believed to be at risk of becoming vampires.
We are much stronger than we look.