Change!!!

The moment we enter a b-school the most cliched phrase we hear almost every day is "Change is the only constant thing in this world". We learn in OD (Hope someone's antenae is alert!!) that organisations need to change in order to prevent death and decline. Remember the theory of Creative Destruction? (oh Man...i should have taken HR). But why dont we accept when human beings change? Isn't it common for a girlfriend( or may be a boyfriend too) to say "You have changed so much! I never expected this from you. You are not the "so and so" I once loved!!"(sob sob sob). But on the other side of the coin lies the need for change. Why does someone ask another to change? Sometime we often hear people making promises like "I will love you for what you are. Never change.. Be this way." Then why do all the complaints begin in a relationship? This is the way God (I am not an atheist) has made each one of us? So why ask someone to change whether for good or for bad? Or is it true that something is really wrong that one has to change to keep things going? Is life really so complicated?