Opposite day! I like Yelp solely because I like to write reviews. I hate Yelp solely because I don't like hearing people, who know nothing about food or the service industry, complain about food and service they think wasn't up to par. It is one of the most obnoxious things I've come across, and frankly, it doesn't sit well with me at the dinner table. In fact, I'd rather dine without.
Yelp was once just a clearinghouse for restaurants, but now it's a community-fueled powerhouse of recommendations for just about anything you can imagine. The users generally write excellent reviews, and Yelp's various tools (search, map integration, etc.) make it dead simple to find exactly what you need.