As everyone here must know, I own a Boxer, Ruby, and boxers tend to be the most energetic breed of dogs there are. It is said that they are basically puppies until they are 7 years old because they have the everyday energy level of most every other breeds puppies. It is because they are a working dog and were bred to work long hours.
Hence, in order to keep my dog well balanced I have to walk her twice a day for over four miles per walk. She is 70 pounds of pure muscle and most people get intimidated around her. Except, she's a big mushball because she lets off all her energy during those walks, she is well loved, she is well trained, and because Boxers are an intelligent breed, much like German Shepards, Poodles, Labs, Huskies, Collies, Retrievers and certain terriers.
You very seldom will go wrong getting a famiy dog that is one of the above breeds. But...... with a dog comes the same responsibilities as that of a parent. You need to raise that dog with discipline, exercise, love, affection, rules and boundaries. If one isn't willing to make those sacrifices of love, don't get a dog.