-Insanely high FPS
-Virtually no lag
-No load times
-State of the art ragdoll physics
Unfortunately, there's a very steep learning curve, and there doesn't appear to be any respawn for dead players.
People these days use "lol" but don't really "laugh out loud" and sometimes they don't laugh, at all, or even make a smirk. So, RL is now being used to differentiate from a boring "lol" and a real laugh.
RL can be used in multiple sequences back to back to show that you are truly laughing hysterically. Example: "RLRLRLRL"
Friend #2: "RLRLRLRL"