Wow! How old are you now? And she's still living in the past? I'd probably just ask if she did any stupid things when she was a teen and if her mother held it against her all the days of her life? If the answer is "I'd never disrespect my mother like that!" Then, say, "I wish I could take back every stupid thing I've ever done, Mom, but I can't. That was over 20 years ago. If I've done anything now that equates that, I'd think we have a problem, but I as a child. But, I'd like to think we've grown past that and have a much better relationship." If that doesn't help, you'll have to understand some things about life. Sadly, we don't get to pick our relatives. If she continues to stay in that place, you can't make her move out of it. After you've given it the old college try to let her know that this is really bothering you, you'll have to decide what you will do if she never changes. Honestly, it's Mom, so you're not going to stop talking to her over this. But, you can control your reaction. If she never changes, have a plan of how you will handle your calls to her and the frequency. When you pick up the phone, take a deep breath before calling her and find something positive to do when you get off the phone with her. It's almost like dealing with a toddler, sometimes you have to redirect them from bad behavior. Change the conversation, and if that doesn't work, let her vent, cry, change subject again, and think about the new color of nail polish you'll wear when you end the phone call.