Vampires were the victims of a disease that paled the skin, caused the gumlines to recede, and sent people into long deathlike comas. If the person "came back," the townsfolk saw not that person but a pale monster with long teeth.
See, vampires can be explained. Sorry, every twelve-year-girl.
I don't really "believe" anything, but I'm open to things unless they can be definitively explained away.
Werewolves might just be a tool of fiction, but the prevalence of beastmen in folklore from most corners of the globe means it's possible they exist. Not likely, but possible.
I don't listen to people talking about ghost encounters, but if a ghost wandered up to me and started a conversation, I wouldn't be disappointed.
That's the way I am with magic. If you can think of some reason that mass and energy can be created despite Ol' Newton, then I'm all ears. Until then, I remain vaguely optimistic.
And please, don't take the lame way and say that love is magic. Love is a mating tool. It's to keep us happy while we make babies. Trust is a survival tool; after all, a band of cavemen is more likely to survive than just one. If love suddenly jumped up and did something inexplicable, though, I'd rethink my cynical opinion.