I'm not afraid to rate 1 star. Frankly if nobody ever rates less than 4 stars then the whole star rating system is suddenly skewed and irrelevant to begin with. This is why ratings systems always end up so controversial and useless in the end. If I can't rate something what I think it deserves then why rate it at all? It's not crap or I wouldn't rate it at all.
I don't know about everyone else, but Star ratings to me are completely Kindergarden in nature. When I was in grade school, any Star on my homework was "Above and Beyond" the grade itself. It was icing on my cake. It was the sweetness above it's grade!
It is a miracle that curiosity survives formal education. - Albert Einstein