If the description makes me think the book is either fantasy or a romance novel I won't read it.  I'm not against love stories but romance novels tend to be gimmicky and I avoid them.  And yes, I do know that every romance fan has that one author that's an exception and I've tried a number of those and they're just as gimmicky as the rest. 
If I read the phrase "perfect for fans of ___" I'll stop reading the description and go look somewhere else for a book unless there's something very compelling in the description before I get to that point.  It's not that I think there's anything wrong with ____ but at that point I begin to suspect the honesty of the description.  Too much hype will turn me away from a book.
That said, I've read a few books based on someone's suggestion after rejecting them based on a description I didn't like and some have been very good.
I do like multi-generational books from time to time.  And Oprah and I like a lot of the same books so I'm not bothered by her recommendations.  I consider them a plus.
The one thing I can recall being mentioned in this discussion that has no affect at all on my decision is the cover.  I couldn't care less about the cover.
Barry