18.
Mn... yeah. My brain and the way it functions is kind of... weird? I mean.. when my sister spoke on and on about Shaman King, it caught my interest and I read it fully, without stopping. I really think it's how people talk about their favorite series, as well as whether or not there is a character that doesn't arrive too late in the story that drives me to continue reading, and even if they appear later, a character to drive me to that point until whatever character appears and I grow fond of them.
Of course there's the plot and everything to take note of as well.
But, to each their own, I suppose.