In all reality, I've eaten larger purchases as losses than some dumb $20 steam game or ebook or whatever. I just don't think that people are terribly unreasonable if they feel burnt badly enough to press for a refund. It's never been easier to do the old "if I can get x number of people to give me $5 each..." bit
Sometimes I read reviews for a restaurant, go, and come out thinking the other reviewers and I have a totally different take on things. It happens.
Same goes for movies, books, games, etc. I "do my research" and sometimes I'm wrong.
And sure, I absolutely sometimes feel "scammed" but to me that's just something that happens.
I'm not too bothered by the idea of demos (eg 2 free chapters), but I am a bit bothered by the idea of "I want a refund if I'm not satisfied enough".
I guess everyone would have a different threshold on what "satisfied enough" is.