As you can see people don't like a series unless it spells everything out for them on sliver plater. That why they only love shitty shounen with hot blood and GAR because their attention spans are so fucking low.
Elfen Lied is story of Lucy learning to coop with the sins she has commented and try to gain forgiveness from the dude she loved. I personally believe that manga was way batter at this and had a more meaningful ending. With Lucy dieing in the guys arms while asking him to kill her and end her suffering...but thats just me.
And for the people the ingrates who keeps saying it's shit. They are just trolling and more then likely never saw it the thirded episode either...