Smurfs, or, "Ethical issues caused by tiny blue people."

Once upon a time games had no matchmaker systems; you joined, you played...sometimes you had even teams and the game was plenty of fun! Other times you had the advantage and got to "ROFLstomp" (a technical term) the other team, and the rest you were the one being ROFLstomped. Eventually enough vocal players decided that they didn't like this paradigm; they didn't like that the majority of their games were becoming either the latter or former...either due to opponents that were not challenging, or opponents that they had no chance against. So developers stepped up and introduced ELO and other history-based matchmaking systems in an attempt to encourage more of those "even" games. This has not been without its consequences, especially for free-2-play games.