The Australian Shepherd is unique with regard to its temperament. There are two distinct types of personality to look for depending on the lines, as well as many shades within these two types.
Generally the breed is an energetic dog that requires exercise and enjoys working, whether it is learning and practicing tricks, competing in dog agility, or any other physically and mentally involving activity. Other Aussies would rather be with their humans and enjoy being couch potatoes. It is usually a sweet and affectionate dog who is faithful to its owners and they are great with children. Most Australian Shepherds make wonderful family dogs, provided there is at least one shepherd-figure to act as a leader and mentor to the dog.[citation needed]
Dogs with strong working instinct may show more reserved, guarding behaviors along with a tendency to chase or nip at running children or strangers if not properly trained. Its protective instinct and behaviors can be frightening to children, strangers, and small animals. Those bred for a more family-oriented temperament are more friendly and affectionate with strangers and generally more reliable around children. Because the breed was developed to serve on the ranch, a job which includes being protective of its property, it sometimes can be annoying with its inclination to bark warnings about neighborhood activity, but it is not generally an obsessively barking dog.
The Aussie is intelligent, learns quickly, and loves to play. This means that a bored, neglected, unexercised Aussie will invent its own games, activities, and jobs, which to a busy owner might appear to be hyperactivity: for example, an Aussie may go from being at rest to running at top speed for several 'laps' around the house before returning to rest, all apparently for no purpose. Without something to amuse them, Aussies often turn destructive of yard or property. Aussies also do best with plenty of human companionship: they are often called "velcro" for their strong desire to always be near their owners and for their tendency to form intense, devoted bonds with select people.
The Australian Shepherd has a reputation as a highly intelligent and versatile stock dog with a range of working styles. While improperly trained or frustrated Aussies may exhibit excessive running and barking, a good working Aussie is quick, thoughtful, and easy with its stock. The ability for the breed to adapt to the situation and think for itself makes it an excellent all-around worker. For this reason the Aussie is often chosen to work unusual livestock such as ducks, geese, and commercially raised rabbits.