Dead Like Me is about a group of "Grim Reapers", basically some people get chosen to do this once they die and must reap an unknown amount of souls before they too fully pass on. George's first reap is this adorable little girl. Earlier in the episode she tries to abandon her reaping duties and save the girls life but later comes to learn that deaths are pre-determined and cannot be undone and that by not taking her soul, she will cause her further misery.
This particular scene is pretty gut-wrenching to say the least. I felt so much compassion for George's character for recognising that taking the life of such a innocent young girl goes completely against her own moral conscience. However the result is bittersweet when the girl is greeted by her own fantasy dreamworld, it left me hoping that I too get my own dreamworld when I eventually die.