Why is it so hard to believe a person can change?

What is with people? Why is it so hard for some people to believe that someone has changed? When did God appoint you judge and jury? I blog every day that you can do anything you set your mind to, you can change you life at any time YOU choose and yet there are people out there at every turn who will constantly pull things out of the past to throw at you.It's like crabs in a barrel, your trying to get out , your pulling yourself out yet the crabs at the bottom dont want you to forget where you come from and keep trying to pull you back down, they hold on for dear life as they have no strength of their own to change their situation so they cant let you change or be happy,  oh hell no we are going to keep stepping on you, pulling you down until you realize your one of us and you will always be, who are you to change , to be happy? not happening if we have anything to do with it!Do you know their story? Do you know they had a horrible childhood?do you know everyone turned their back on them? Do you know they lost everything and were homeless? That they lost people they loved  and felt unlovable? That the knew everyone talked about them when they walked into a room? No you know none of this nor do you care because they are happy and you are not and that will never happen on your God appointed watch!They survived all of that and much, much more, they pulled themselves out of the bottom of the barrel, decided what was important in life and kept fighting to change, to become a better person, to ask for forgiveness and forgive all the others that hurt them.That each and every day they tried to be better until one day they met someone who believed in them, who knew about all that was in the past and still wanted to be there, that had their back and encouraged them that yes they could do it, that they could could do anything because they knew his heart and what he truly was in his soul.This made him want to be the man she saw when she looked into his eyes, this made him believe it was possible to be loved no matter what was the past.It made him work that much harder to keep going down this unknown path of change.Yet here comes the crabs once again , hey you cant be happy,  do you know what you did in the past? Wait let me remind you and everyone else who will listen, You can't be doing so well, we are down here struggling to survive,  no, no that's not happening and they pull you down some.I am here to say loud and clear, you no longer need to look back , you have climbed out of the barrel, shook loose of all the the last crabs holding on and you will stand tall and proud of who you are today and how far you've come to get here.  You will no longer look down or worry about what someone else has to say, you know what God sees in you and what I see in you, you will know you are good enough and that its okay to be happy. The barrel is behind you and there will always be the crabs left behind calling out to you but you can't drive the car if you keep looking into the rear view mirror. Let it go, you have a wonderful bright future ahead of you, you just have to believe!