A phrase used to demonstrate toward another person that their existence is useless, can also be used just to put down someone, make public their lack of intelligence , or make them hate their life altogether. Most frequently used right after telling somone "your head a splode" during a multiplayer video game. This phrase also encourages the person who the phrase is being directed towards to try and find something to do with their time that will make their life meaningful.
Person 1: "HA! HA! I JUST STOLE YOUR FLAG!"
Person 2 shoots Person 1 in the face with a shotgun.
Person 1: "WHAT THE!?"
Person 2: "GET SOME LIFE!"