Following on from my previous blog I'd like to offer my first sequel. Not quite The Empire Strikes Back, but you get my drift...

It's accepted that there were many major turning points in Anakin's life, but two of the major one's were leaving his mother Shmi behind on Tatooine and her death ten years later at the hands of the Tusken Raiders. In the first instance fear and longing filled Anakins emotions, feelings that Yoda warned him against. In the second instance, the rage and anger that Yoda sensed surged to the surface and engulfed him. The loss of his mother was a pivotal moment in his descent to the dark side, and because of his intense love for Padme he swore never to let it happen again.

But as I discussed in my previous blog, Anakin suffered not only from his mothers loss but the lack of a true father figure in his life. A strong male could have guided him and molded him, along with his mothers wise council. Perhaps Anakin sensed the attraction between Shmi and Qui-Gon, a bond that was brief and broken by Anakins departure. Perhaps there was an element of resentment - after all, Shmi did allow her 9 year old son to be taken away without her (even though he longed for adventure).
But maybe it wasn't the maternal figure in his life who let him down, but the paternal. Look at the facts of how he was let down by the men in his life (and bear in mind, these observations are all from his own 'point of view'):

Watto - His earliest father figure who gambled him on a pod race.
Qui-Gon - Who died on him, leaving him alone.
Obi-Wan - Who he believed betrayed him, along with the Jedi Order.
Palpatine - Who lied to him about creating life and enslaved him to the dark side, making him a slave once again.

You can see the pattern. Anakin had no true father, and the males in his life all let him down to varying degrees.
After the death of Padme he had nowhere else to go. He himself had destroyed the Jedi, it's future, himself and any chance of immediate redemption. He had allowed his hate and anger to consume him and draw him deep into the dark side.

But fast forward to the very end of Return of the Jedi. After all the evil that has occured over the past 23 years he stands face to face with his son Luke.
Think about it. Luke knows he has a father. He was born of a union between Padme and Anakin, not born of the Force like Vader. Anakin never had the opportunity to question his father, to love him, to even know him. But here was Luke, risking all for a greater cause - Anakins soul and the fulfillement of the Prophecy of the Chosen One (although we as fans know Luke would not have known about the prophecy - but Ben and Yoda knew full well what was really at stake.)
Luke has defeated his father for the first and final time, and has rejected Palpatines offer to kill Anakin and take his place. Luke refuses, throwing away his weapon and the Emperor lashes sith lightening upon him. Luke is about to die, and cries out "Father!"
That is the moment. Watch Vader carefully. It's clear he has a million things going on in his head, but until Revenge of the Sith we could only partially guess what thoughts. But now we have a better idea. He would be running the events of his life through his mind - the Pod Race, Geonosis, The Invisible Hand, Mustafar, The Death Star, Bespin - everything that happened to him that led him to this point.
Would it be impossible for him to be thinking about his relationship with his son, and also about the father he never knew? Anakin never had a father who could rescue him, and yet here he was watching his only son die. Along with a thousand other thoughts, isn't it possible that this helped weigh the scales towards the end of the Emperor, the Empire, the Sith and his ultimate redemption?
In short, wasn't the life of Anakin Skywalker dictated just as much by the absense of a father as it was by the loss of his mother?