I don't believe we humans are good by nature. Most people would do nasty things if they knew there are no consequences to their behaviors.

We humans have a part of the brain called the pre-frontal cortex that modulates our instinctive behaviors and thoughts. We cannot prevent the instinctive impulses, but we can control them to be part of a society and to cooperate with others. If you mean by being natural and free spontaneous and genuine, then I agree. But if you meant to express every impulse you have, then I disagree. We need to put some mask to interact with people, by keeping our inner cave man/woman under the surface.