I started reading because I saw all three seasons and the OVA (both subbed and dubbed) and loved it enough to continue. The first arc I ever read was the Campania arc, and I read the rest for nearly a week straight. I was lucky enough to see BOA in theaters and bought a ticket as soon as it went on sale.
No other series has grabbed me like the Black Butler manga has. The art and designs, the paneling (makes it really easy to follow for an American reader), the characters and camaraderies, the antihero motivations, the intertwining storylines, the action, the FANTASTIC foreshadowing, all of it is just gold. The only downsides are the monthly releases and Yana being the queen of cliffhangers.
If you picked up this series on a whim and are still reading to this day, then congratulations, you have taste :)
I started this story because I like Sebastian. Just that simple reason. But the deeper this story goes, that simple reason's becoming more complicated and I can't stop reading it. I feel like cursing those bastards!! WHYYYY!!!! My heart can't take this... ╥﹏╥