Questions seem eternal

Have you ever looked back and just think why the hell did i do that??? why did i lose that friendship....why did i push them away..or push myself away?...I probably could of been a better friend,sister,daughter,coworker....etc.. These are the questions i find myself filled with lately..I cant help but, find myself looking at pictures of old friends...the memories...the laughter..tears.. and betrayal.. Sometimes you find yourself hating who you have become.. knowing these experiences make you a better person..but still you have this big blank check that says VOID...inside of you.. some people think that means low self esteem or some religious reason...but isn't it just you?..me..us... humanity.. our trapped hearts unwilling to let go.. when will we be able to get to that point of telling that person..friend sister whatever that we are sorry...we should of tried harder ...we should of understood..to not criticize..not judge..just be there for each other.. why is this idea so hard for people to soak up?...its not brain surgery right?..or maybe it is I want to become this person again...who was so forgiving..uderstanding..I want to let go of the bitterness from my past.. because.. if you think about it how will anyone ever find any type of happiness when they can't let go of those things or people..or situations.. that they hated?.. what is the cost we will put on our friendships..our relationships?...will we ever realize its worth until its to late?