Here's a link to our paper at KDD 2013 looking at why people hate your app. We crawled user comments on Google Play for about 100k apps, and then did some clustering and linear regressions to probe what people say when they give you low star ratings.
It turns out that a lot of low ratings often come right after an update, when people find out that their app doesn't work anymore due to incompatibilities. We also found some odd anomalies, like people saying they love your app but gave you a 1 star rating. If you want the very short summary, jump to Table 6. We divided up the comments by app type. For example, for games, people tended to complain about (1) attractiveness, (2) stability, and (3) cost. For other categories, the complaints were less consistent.