I am a bit like Geralt. I very rarely do not finish a book and I am overall much more likely to love what I picked to read or at least like. My average rating on goodreads is 4.1.
It is because of the vetting process I have. It works mostly. I might still get a 2 star read here and there and some 3 stars, which to me of course are still liked it. But overall I am pretty happy with most what I read.
There is no way I am going to waste my precious time reading sample after sample. That would take all the joy out of reading for me.
I guess I am at the stage where I know what I like and I want to read what I like. I know what I don't like. I also have other like minded reader friends that I can trust, mostly. There'll be the ones they loved and I didn't, but that goes both ways.
I get bored easy and have always had issues sticking with things to the end. So I need my reading to be solid or I'll get stuck in a never finish rut and I can't get out. I don't want to stop reading. Its the hobby that's like my lifeblood.
That is why I never read samples. I think I can count on my 2 hands the amount of samples I read since reading kindle books starting in 2008.
I am a bit OCD about not reading parts of books, but full books. So I need them to be good.