There are many reasons to not want to get a dog.
1. They are expensive food, grooming, vet bills can be things to consider other than just the initial cost.
2. Barking, chewing, and other destructive behavior if a dog is purchased without regard to their breed. Example: herding,working,etc.
3. Training if getting a puppy. Will the dog be crate trained?
4. Exercise all dogs need exercise to be content. Who will extensively walk the dog, take to the dog park etc.
5. Poop... yep. Who is going to pick up all the stuff in your yard unless of course you have a tiny toy poodle.
6. Some dogs do not do well be left alone for prolonged hours while family are away at school/ work. It’s called separation anxiety.
Study the breed you want before you get one.
It’s hardly fair to expect everyone to be thrilled about getting a new pet.