Fun fact: In Eastern European folklore, vampires are actually obsessive counters, and when Jim Henson created Count Von Count, that was part of the inspiration.
Roma used to scatter coins or colored stones around their campsites, so that any approaching vampire would be distracted and spend the night counting the things, before fleeing home at sunrise.
So basically, a side effect of becoming a vampire is becoming OCD.
Of course, in these same traditions, vampires are addicted to poppy seeds, and a similar ring of seeds will fend them off at night, so it seems that they get stoned easily, so it's all about the give-and-take.