BoP said it well. There's an old saying, 'Rarely do members of the same family grow up under the same roof.' Forget blood. You have oodles of blood relatives out there you'll never know. Even the ones you do know are most likely virtual strangers. My sire is a shitheel and I've never wanted anything to do with him, so I haven't had anything to do with him. All your real friends in this world you can likely count on one hand. Everyone else is an acquaintance of varying degrees. Who'd take a bullet for you? Who'd give you the shirt off their back if you needed it? I have just three people in my life that fit into that category. Everyone else is nothing more than a fairweather acquaintance.
While it's a lot rarer to have a shitty mom than dad, it happens. Not everyone wins the great mom jackpot. I've known plenty of people who fucking hate their mothers. Learn to let go. Learn to move on and not waste time on it anymore. Don't sweat the small stuff.
“With the first link, the chain is forged. The first speech censured, the first thought forbidden, the first freedom denied, chains us all irrevocably." - Aaron Sati