What do vampires mean to you?

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Vampires could just be a fun folklore thing. If they're more, what is your favorite application of vampires as symbols, metaphors for themes? Or what is the best part of drama that vampirism brings to a story?

Capitalism, rich feeding on the poor?
Foreigners, fear of external blood corruption?
Addiction, gluttony and feeding off others?

Do you prefer to focus on the immortality and the problems therein? Predatory nature?