People are more likely to write about a bad experience than a good one.

People are more likely to write about a bad experience than a good one, so the ratings are inherently skewed to some extent. If you had a good experience with a company, you probably will thank them over the phone or personally, and then turn to enjoy the goods or service received. You become absorbed in that (your new car or smartphone etc), unless the company prompts you to rate the good experience on this platform, you are not going to take the time to bother. But, a bad experience means, you can't wait to tell the world about it - its human nature.