All dogs bark, but a dog barking continuously for several hours is a nuisance. Imagine a neighbor with an infant trying to nap, or one who must sleep during the day because they work a night shift, or one who works or studies at home and must concentrate. It's one thing to play with your dog and have some momentary yipping, or to allow your dog several woofs to alert you to the mailman, but it's terribly inconsiderate to leave a dog outside for hours on end and allow him to bark, whine, and howl. They commit to owning a dog for its entire lifetime. Many puppies are purchased or adopted on impulse, only to be given away, sold, or dumped at the pound when they've outgrown the cute stage and begin to manifest behavior problems.
Dogs require time, energy, and money to maintain.
The responsible pet owner evaluates their life situation before bringing home a dog. They provide appropriate food, shelter, and veterinary care. Far too many dogs are obese. Many people don't think of putting a coat on their small or short-haired dog when they walk it on a cold winter day, even if the dog is shivering. Conversely, many dogs cook to death in cars on hot summer days.