I don't want to clean up after my dog after I walk him.
That's not good. Why don't you want to clean up after your dog anymore?
It's messy and I don't think I should have to clean up after him.
Part of being a responsible pet owner is cleaning up your pet's waste after you walk him. I know it's unpleasant, but it's part of being a responsible pet owner. You can't expect others to clean up after your pet.
Fuck you and everybody else for making me clean up after him.
I can see that you are upset about having to clean up after your dog. But think how others feel about having to clean up after something that belongs to somebody else. It would feel worse.