We just adopted a dog, I don't want it.
That's awful. What are your feelings on the dog?
I don't like it, maybe I'll keep him for a while, but it barks too much.
You should be there for that dog. Don't abandon it. You should keep your commitments.
Nah, I don't want to. I'll probably give it away soon. It was my mom's idea to begin with.
It doesn't matter how it came to be, you adopted it and and you should be more responsible. If you didn't want to be responsible for it, you shouldn't have adopted it.