I just got a bit bored and not eager to pick it up. 

It just wasn't capturing my interest as much as I'd have liked. Felt like an effort to read. It's perhaps a book for another time. 

Just was never bothered about going back to it and didn't like the short story style. 

42%
Wasn't enjoying it enough. Half the time it felt too YA and cringey. The other half felt too over detailed in the scientific stuff that it was making me switch off. 

Wasn't invested and not in the right mind frame. Not enough to keep me wanting to read. Too doom and gloom without let up. 

A fascinating book and one that definitely needed to be written. 
However, I just wasn't getting much enjoyment from it and it had taken me about 3 months already to read 30% 
I think I need more escapism in a book especially when my health anxiety is so high. 
Feel guilty for it being a DNF because it is clearly important and well written but sometimes you have to step away from a book you can't quite carry on with. 

Was just bored

Just not getting any enjoyment from it and I'm over a third of the way through. Not the book for me. 

Felt like a chore to read and the content just really wasn't interesting enough for me. 

Just wasn't enjoying it enough and it felt like a chore to read.