If there was a god, would I be able to blame all of my shortcomings on him? Sounds like a copout to me.
At one point in my life, I believed that one could not really change their true nature. I still believe this to an extent, though not as fully as I used to. What would be the way to do it? Perhaps by acting one way until it becomes natural for you. Or maybe by erasing everything and becoming a blank slate once again, tabula rasa style. Who knows. If it truly is possible, I do hope to figure it out some day.