Why?

Why do we continue to let people hurt us, knowing what they're capable of? Why do we continue down the endless cycle of self-destruction when we know exactly what the outcome is? Why do we let people tear us down and belittle us when we know we're worth more? Why do we allow people to take advantage of our kindness, knowing that you can't change people, only people can change themselves? I've thought this over time and time again, I guess I have more sense than some people. I won't tolerate anyone treating me bad, I won't stand for people who are only about self. Life is an ever-changing experience, everything happens for a reason I believe. And with that change comes a new outlook, another aspect of life for us to experience as an individual. So why is that people seem to be stuck in one place, even when they have the opportunity to do something different, to change something about themselves or a situation? Why does Miki allow herself to get caught up in the same BS when she knows what is going to happen, or how about Mannie who seeks any kind of companionship and still gets burned everytime. How about Dee who knows that his relationship is on the verge of unavoidable destruction each and everytime his spoiled brat of a girlfriend gets angry? Why does the X who suffers from low self-esteem only get her hopes up everytime she sends him a text message only to be shot down miserably? Sometimes I think that in certain situations, people don't hurt people, people hurt themselves. We know how unreliable and selfish people can be, and yet we set ourselves up to be disappointed, thinking that maybe you can change him/her if you loved more, did more, gave more. Why?