Neither is lazy, and neither is a machine. The difference sits on the physical level of the profile, the temperament: how much pressure a person can carry, how they respond to it, and how much activity they need in order to feel like themselves.
One person is built for short, intense bursts and recovers in the pauses between them; another is built for long, even effort and only tires when interrupted. Both are perfectly healthy ways to be made. The trouble starts when one of them is measured against the other, in an office, in a family, or in their own head.
Once you know your own rhythm, the question stops being "what is wrong with me?" and becomes "how do I arrange my day so that it works with me?" That is usually a much easier question to answer.