The Five Precepts are the basis of Buddhist morality. They are not all of it. We start by recognizing our bad behaviour and striving to stop doing it. That is what the Five Precepts are for. After we have stopped doing bad, we then commence to do good. Take for example, speech. The Buddha says we should start by refraining from telling lies. After that, we should speak the truth, speak gently and politely and speak at the right time. He says:

“Giving up false speech he becomes a speaker of truth, reliable, trustworthy, dependable, he does not deceive the world. Giving up malicious speech he does not repeat there what he has heard here what he has heard there in order to cause variance between people. He reconciles those who are divided and brings closer together those who are already friends. Harmony is his joy, harmony is his delight, harmony is his love; it is the motive of his speech. Giving up harsh speech his speech is blameless, pleasing to the ear, agreeable, going to the heart, urbane, liked by most. Giving up idle chatter he speaks at the right time, what is correct to the point, about Dhamma and about discipline. He speaks words worth being treasured up, seasonable, reasonable, well defined and to the point”.

MI 179