-the entire game slows down or pauses for everyone
-you cannot compete fairly against the lagger because their character, or characters seem to skip around the game, seemingly defying the laws of physics
-if you are the lagger, you will often times unknowingly be defeated due to the fact that you cannot accurately control your actions in the game
Sometimes laggers lag on purpose to create an unfair advantage over their opponents. There are methods and ways to lag a game so that people can't see what they're doing - yet the lagger can still play normal. This is considered cheating and if caught, the players will be banned or suspended from playing.
Lagging, whether it be on purpose or just because you're poor, is frowned upon in the gaming world.
Lagger's Team: Yay!
Legit Team: Dumb noobs.