Stands for "I hate you so much right now". Usually used when you hate someone at the moment of speaking and you want to inform him/her. Comes from the song Caught Out There performed by Kelis.
You are such lucky bastards every time we play table football! You win again?!?! IHYSMRN!!!!!!!!
When you fail at something in life (eg. failing an exam or not getting a job), go home and spend an hour just standing in the shower, propping yourself up against the wall with your eyes on your feet.
Caleb knew the only thing to do after he didnt get prefect was take a failureshower.