What's the most frustrating experience you've had playing World of Warcraft? Did it involve other players not behaving as they should?

With PlayRate you can give people you have played with in a group or raid a rating. The cool part is that your ratings are transmitted to other users of PlayRate and you receive their ratings as well. PlayRate will build a database of ratings it receives while you are online and you can synchronize the database at www.playrate.net to get ratings that were given while you were offline. This enables you to check out what a player's average rating is before deciding to invite him to a group. If a lot of people install this mod the idea is that people will refrain from behaving badly because they know their actions will not go unnoticed.