I have a few that I never finished..
Harry Potter, 50 Shades, Twilight,
Almost anything by Stephen King. He has a tendency to just go on and on sometimes. I don't necessarily find it boring, but it's hard for me to get through so I don't pick up anything by him very often
I almost never read the classics either. I haven't tried to read one in a long time but I know as a teenager I had ZERO patience for them