The world's worst vampire hunter...
Harker almost deserved to be bitten. He doesn't realize that Dracula's wife is a vampire and allows her too close to his neck. He shows Dracula a picture of his fiance, putting her in danger. He doesn't wear a cross or carry anything for protection. He comes to kill Dracula in the early evening. He kills the wife first, the weaker of the two creatures, allowing Dracula time to wake up.
Seriously, everything about that guy says "BITE ME PLEASE!!!"