Is it normal to play favorites?

It starts with my maternal grandma .. She has 5 kids and she plays favorites she is illiterate and never owned anything in her life she's late 70s now. She only favors my aunt who is the only successful one in the family and my grandma only cares what my aunt and my aunts husband can do for her because they sent her on a vacation one year for her bday so now she expects it all of the time. Now it's a trickle effect on to my kids because my grandma favors my oldest daughter and has turned her against me. My grandma pushes my other kids away and my grandma acts fake toward them. We moved far away from her 10 yrs ago and the rest of our family on her side because none of my grandmas family gets along she drove a wedge between her own kids and she tried to do the same with my kids. She lies a lot and she sweeps family issues under the rug all except the fact that she turned her own daughter away because her boyfriend of many years ago slept with her daughter ... Her daughter which is one of my aunts was 18 at the time and my grandmas then boyfriend was a few years older. Grandma is illiterate so she always dated men 20+ years younger to match her intellect level. When I was cool with my aunt my grandma forbid me talking to her and never told me why but now I know. Grandma is a trouble maker and I found out she talks behind ppl in the family's backs then if they cater and ass kiss she will be fake to their faces. Since I've been in a different state she does not call nor visit but she will pretend to care and keep in touch with my daughter and tell her she misses n loves us. It's a lie. When I went back to my hometown for my brothers funeral 2 years ago we stayed with grandma and after the funeral grandma started an argument with me to get me to leave smh. She didn't care that my brother died and it was her grandson. Now my mom is sick in a nursing home and that is my grandmas daughter that she never cared about before but all of the sudden she is pretending to be so concerned and I believe it's only to get self pity because I spoke to grandma the other day and she kept talking about my mom saying how her daughter is so sick she may not last a month smh my mom been in the nursing home 4 years now so why now grandma is acting as if it's gotten worse is beyond me. My mom is worse than my grandma .. She didn't raise me and she treated me bad my entire life because her mom which is grandma is crazy too .. Neither of them had good parenting skills and my mom wrote me a letter years ago and told me that I am a product of rape and should have been aborted but my family says I'm wrong for not visiting my mom?? Really ok . I'm not fake like the others and if I haven't been talking to my mom then I'm not going to start just because she had a heart attack and a stroke and ended up in a nursing home and wheelchair before the age of 60. My mom was abusive to me and my siblings and neglected them beat them didn't feed them and my grandma and family didn't do anything about it. Now they feel bad for my mom? I'm sorry but I can't feel for her . And grandma is just as bad with her favoritism and the things she says and does and has done in the past. Grandma was mean to some of my cousins growing up she never treated anyone fairly she always pick n chose who was her favorite. She drank a lot and partied and did drugs infront of me growing up she was in her 40s dating a 19 yr old man smh and she put him on a pedastool and when he had sex with her younger more attractive daughter she kicked her daughter out of the house and kept that boyfriend of hers there and he used to beat my grandma then after he left my grandma and married a younger woman my grandma stalked him and used to make me go spend the night at his house she used to tell me he loved me and I was like his daughter. Smh she was just doing whatever she could to stay involved with him and he never hurt me he was cool toward me he spoiled me and took me shopping but I know she made me spend weekends with him thinking I'd come home and tell her everything he was doing she's very nosy. When he left her and bought a house she used to drive there and I was in the car and she would peep in his Windows .. She is a weird woman and if ppl who know her now only knew what type of person she really is. Also about 15 years ago i found some of the ex boyfriends personal stuff hidden in her room his old bandana and drivers license smh she needs help she is so weird and crazy. And my family thinks I'm the crazy one cause I speak out about things that went on. I don't sweep weird family issues under the rug like they do. My grandmas dead son molested me for years and she knew but didn't do anything and when I got older I confronted her and by then he was dead and all she said was " he's dead now what do you want me to do about it ". Smh I tried to love her but after all that went on its hard to and I honestly can't stand her.