* The end where a 10-year-old Boba Fett is seen picking up his father's helmet.
* Shmi Skywalker's death. You could totally understand why Anakin would do what he did next (even though it was horrible itself) after having his mother die in his arms like that.
* Anakin's pain, rage, and grief is so strong that Yoda can sense it on the the other side of the galaxy, and hear Qui-Gon's spirit calling out to Anakin through the Force, trying to stop Anakin from taking revenge.