There is no point too obvious to be a requirement. And vice versa. Just because a requirement is obvious to you, doesn't mean it's obvious to everyone. A project begun without a statement of requirements will end with unpredictable results. Without good requirements, cost estimates cannot be reliable.
Requirements often involve confrontation between interested groups.
That's one reason they are so important. Requirements are Not Requirements are not descriptions of how needs are to be achieved, that is design, but what is to be done and with what quality. Requirements are not design details, such as exact screen or report layouts. It is easy and seductive, especially to techies, to leap into design before knowing fully the requirements. Wording Requirements 'Shall' and 'should' are special words often helpful in Requirements.