You know you probably won't finish a book when...

[WaterBird]

It usually takes you several days to a week to finish a book you like, but it's been almost 3 weeks since starting the most recent one and your phone app tells you you've read barely a quarter of it.
I might just look up the ending...

Life is too short to read a book you're not enjoying. Give up and find a new one

I think reading a quarter of it means that you've given it a good enough chance. Put it down, pick up something else and try again after a couple of weeks or so and, if you still feel the same, it's not you...it's the book!

Thank you all. I went to Goodreads to look at the ending, and it seems like there's a funny part so I'll give it one more chance.
The writing style is actually very good. It's the main characters who are annoying me!

What is it, out of interest? Not that I want to avoid it or anything...

@dontpointatme
It's We Were On a Break, by Lindsie Kelk.
This fairly young couple are having issues, but it's purely because they can't communicate, and it's not like any of them did anything bad...