I'm done

Why is it that so many people can not accept this statement. I'm done I'm tired of pretending. I don't want whatever it is that your are currently offering, and whatever it is we had it the past is done.
Why is it that people can't say this for themselves and have to go on pretend that things can be what they never really were in to start with. Why is it that the same people who can not say these things for themselves keep looking down on me, so to speak, for being able to. I'm just so damn sick and tired of it. For my own piece of mind I never completely done till its been over for a long time. Relationships friendships whatever they are all basically the same.
You can love people who are not good for you. You can have friendships that last 10, 15, 20 years but do not last a lifetime. People can change, you can change. Then you can just not fit into each others lives anymore.
Maybe one of you just refuses to keep playing a part you just don't want to play anymore. You've given everything you have in you to give and you just can't take it anymore. Maybe the friendship existed inside of such a tight bubble that once the enviroment all the relationships in side that bubble changed to. Some of them grew stronger, some stayed similar, some could not be repaired. Sometimes it doesn't matter what happened, and sometimes it does.
I wish people would understand that when I say I'm done I'm done. I'm done with the relationship as it is. I have no desire to pretend we can go back to the way it was. Once you start looking forward you can never go back. If you'd like to move forward I might be interested in giving that a try, but I didn't say I was done for no reason. I can accept responsiblity for my failures, but I assure you I'm not the only one to blame. For me to say I'm done means I've already tired to make things work to the best of my ablity. I've accepted responsiblity where I'm capable of doing so, but no longer am able to take blame for things I have no part in. I will not apologize for something that I didn't do. Someday we all have to look in the mirror, and accept responsiblity for our own failings. I've done my part. I've done all I can do. If you choose, or have choosen to not do your, then to you I say I'm done. I'm tired, and I just won't take it anymore. And to those who don't choose the same thats already its your choice to make and I understand, just leave me out of it.