It looks like Google got a bit lazy in choosing their "Best Apps of 2015 for the Google Play Store." From what we can tell these lists where auto-generated based on ratings, downloads, and popularity in their category, instead of being "hand-picked." Basically, the apps that made the list this year were all "safe choices."
Most of them are excellent, (we especially agree with Robinhood, HBO Now and a few others), but a few could hardly be considered the best of the year. Here's a link to peruse the list: Best Apps of 2015 - Google Play
Be sure to come back and let us know what you think of Google's "choices."