i was thinking about it the other day, and i think i underestimate apollonia's impact on michael. at first, i didn't think he truly loved her completely, i just think he did it out of necessity. the man had not dated in a while, didn't know when he was going home. but i think about it some more, and i do think he really loved her (from his actions in godfather part III and also the deleted scene from part I).

similarly, i underestimate the effect her death had on michael. i think this made him hate his father's enemies all the more, and made him want to exact his revenge. also, he seemed so much more innocent before her death. it must have really shook his faith in God and in humanity. the woman you love and want to spend the rest of your life with and raise your kids with....dying...that must really suck the life out of you. maybe this was the real defining moment that sucked all the love for life out of him, and turned him cold.