My mother was a very unhappy person for the majority of her life, and our relationship as I grew to adulthood was not good. In fact, I didn't speak to her at all in the final four years of her life. I was an only child, and she just dumped all her unhappiness on me.
Choosing the worst thing she said to me is tough, because she said so many mean, ugly things. I guess the very worst was during a conversation we had in a grocery store, about the guy I was dating while I was in college. To me, he was a sweet, gentle, loving person with a great sense of humor, but to my mother, he was the potential father of her grandchildren, so the conversation started with her asking if we were serious. I told her I didn't know, so she said she thought I shouldn't be serious about him, because she didn't want bald grandchildren. (He shaved his head, but was mostly bald on top.) I told her that was the worst reason ever for not being with someone, especially since neither of us was interested in having children. Mom exploded: how dare I say I wasn't interested in having kids? Didn't I know I would be depriving her of grandchildren. HOW SELFISH! She went on and on about how selfish I was for not wanting children. I told her I didn't think having kids just so she could be a grandmother was a great reason to have them, but that just made it worse.
Didn't want kids then, and never did get around to having any. Mom's desire to be a grandmother didn't enter into that decision making process, but the thought that I might not have the right role model for motherhood certainly did.