Nature understands the nature of human beings, which is why it knows which shall be harmful to them, and what quantity can benefit them all. That is why, Islam has put Limit (Shariah) on every thing ONLY for the benefit of communities on a large scale.

While limits are in place, yet exceptions for one off scenarios, too are permissible under the Shariah. For example:
A traveler is allowed to offer a short version of prayer, a patient is allowed to avoid fasting, a non affording person is exempted from the pilgrimage and zakat is applicable on only the people having surplus.