What is You Would Know?
1.
Something commonly said to someone if they happen to be knowledgeable on something sad, pathetic, or sick.
Brian: Hey Joe, Why do you play computer games all your life?
Joe: What the fuck are you talking about? It only takes an average of 4026 hours 43 minutes and 7 seconds to get all the max levels on runescape.
Brian: You would know... you would know...
Example 2
Conner:There are so many date rape drugs these days People who use them drugs are just sad because they can't get any.
James: Um...rohypnol, ketamine, burundanga, and rohibitril are the only ones commonly used. Besides they only knock someone out for a max of 24 hours... so don't talk shit about date rapists.
Conner: You would know... you would know...
See
