I'm always kind of annoying when the protags don't have much confidence or when things got very slow...
I know problems, missunderstanding or something similar is necessary to the plot... But sometime I don't like it when the protags blame themselves for something bad that happened (like Cana in the last Chapter)
When it's happened, my first instinct is always to drop the series.
That's what I did to Doc Elise. I started to get annoyed by her actions and drop it at the last chap.