The episode is so amazing because all of the storylines are connected and make another perfect episode that is worth watching and remembering.
Meredith and Derek have sex in Meredith's apartmen but even trying to hide it,everyone realizes and hears them.That causes Izzie to tell Meredith that she thinks taht she is the best intern because of her relationship with Derek.
George suspects a doctor drinking on the job and has difficulties with revealing it to the others.
Alex treats a former schoolmate who finds honor in self-mutilation.
Izzie has to deal with a patient who won't let his girlfriend go, literally.
Cristina seems to be battling a case of the flu which reveals its true nature with a couple of positive pregnancy tests.
A great episode with scene that i will enever forget such as the fight between Meredith and Izzie,the first time Alex showing his heart and soul and the dramatic side of his character-a truly character development for him and the pregnancy of Cristina.