To illustrate what I said above, I opened the Google Play store, took the first app on the main screen ("My Talking Tom") and searched the first 1-star in the ratings:
"Je met une étoile car le jeu me plaît vraiment mais le fait que les applications proposés pour gagner des pièces ne rapporte rien est décevant et décourageant pour ceux qui ont passé 2h à réaliser la tâche demander..."
In english:
"I put only one star because I really like the game
but the fact that the proposed apps to earn coins bring nothing is disappointing and discouraging for those who spent 2 hours to perform the task request..."
Question: what note would he have given if he had not liked the game? We're fortunate there's no 0-star rating... A link to another app that does not work properly and you have the infamous 0-star !!!