Joy, excitement and hyperactivity should be distinguished.
Joy is positive feeling, cheerfulness, great happiness. The mind is settled, under control, the individual does not feel anxiety. On the other hand, excitement is a state that is expressed by trembling and overwhelming emotions that very often cannot be controlled. It can lead to sudden movements and reactions. Usually, excessive joy can turn into excitement.
Excitement is not the same as hyperactivity, but constant state of thrill is. A dog is not focused, it runs around looking as if it does not know where to go or what to do first. Such dog is out of control in many segments of its behaviour. Once it is out of control it means it can be dangerous to other animals and humans, as well as danger to itself.
In wilderness, dogs do not act hyperactively. Such energy is not natural. Excitement is, since it is momentary, but hyperactivity is not, since it is lasting.
Reasons are different:
Humans often do not distinguish playful and excited dog. They think it is happy and with their reaction – commonly with the best of intentions – they encourage this problem.
Not enough walking causes accumulation of energy which pulls the dog into frustrated state that can be the cause of hyperactivity.
Also, if the dog is insecure, it can turn into hyperactive state. Insecurity makes that calmness turns into anxiety which is, actually, artificial additional energy.
This problem can lead to other behavioural problems.