A decision is usually derived from a individual's lifestyle, and not just because of the owner. Different pets require different needs that need to be fulfilled on both psychological and physical realms. This is the reason why many cat owners live in small homes yet do not feel guilty about their cat's environment. On the other hand, it is considered cruel to leave a dog locked up in a small place for long periods of time.
An ideal dog owner is enthusiastic about the great outdoors and makes great efforts to walk said dog at least three times a day. As a matter of fact, one of those walks should be particularly long and give the dog a sense of adventure and exploration which the owner might also enjoy. It should then come as no surprise that in contrast to many cat people, dog enthusiasts don't mind getting their hands dirty and playing with their dogs in a more rough fashion. They also try to establish the act of playing as an outdoor activity.
Cats aren't usually permitted to go outside and playing with them is usually a lot more low key. Buying small knick knacks and toys and hanging out in the living room usually describes a day of stimulation with this smaller type of animal.