Books I Regret DNF'ing

There are some books that I am glad I did not finish, but others, I painfully regret not finishing them. I feel like I didn't give some of these a fair chance, and even though they had promising storylines, I still ended up giving up on them. Here I some books I wish I had finished:

Etiquette & Espionage
Author: Gail Carriger
Genre: YA steampunk
I've read the synopsis for the upcoming second book, and it really sounds interesting. I remember reading this back in March, and I didn't have a good reason for not finishing this. Maybe I'll try this again one day!

Shades of Earth

Author: Beth Revis

Genre: YA sci-fi

I enjoyed reading the first two books of the Across the Universe series, and I'm not quite sure why I didn't finish this last installment. I feel like I'm a disgrace to this series since I consider myself a fan of it. 

Through the Ever Night
Author: Veronica Rossi
Genre: Sci-fi/dystopia
I gave up on this second book of the Under the Never Sky series due to the fact that the author didn't explain things very well in the first book, so I was a bit confused at the beginning of this one. Based on my friends' reviews, it seems that the author actually explained everything, and it started to make sense. Plus, most of my GR friends gave this book 4 or 5 stars.

What are some books you guys wish you didn't DNF, and you feel like you didn't give it a fair chance?