I think my mom's being a selfish brat about her dog
What's so bad about having a dog?
My mother got a dog late in my childhood. It's always whined for food and I hated it.
While you can be annoyed at how your mom treats her dog, it isn't appropriate to call her names as family members should try to be respectful to one another. If you don't like your mom's dog, you should try to be more open minded and at least make an attempt at bettering your relationship with the dog since your mom cares about it very much. If you have a better relationship with the dog, you can better understand your mother and why she treats the dog the way she does.
I never said I hated the dog. I said I disliked it. I don't need to be nice to my mother's dog since I won't get along with it.
But you did say you hated it in your last message. If you don't like this dog, you don't have to interact with it. It's your mom's pet, so why not just let her have her joy, and you have yours instead of calling her names?