Bhikkhu Bodhi and Bhikkhu Nanamoli translate the Pali word kilesa as imperfection, where some others use the word defilement. The list we’ll be using is from the Vatthupama Sutta (MN7).
Imperfections that defile the mind:
(1) covetousness and unrighteous greed
(2) ill will
(6) a domineering attitude
(13) conceit (mana)
What’s the value of considering each of these negative qualities? As the sutta says: When the mind is undefiled, a happy destination may be expected. In other words, our own happiness depends on finding ways to abandon any of these pollutants that we can discover in our own minds.
The sutta goes on to say: Knowing that [each imperfection] is an imperfection that defiles the mind, a bhikkhu [practitioner] abandons it.
Further along in the sutta, someone asks whether bathing in a sacred river can wash away the defilements. The Buddha replies in verse, the last stanza of which is:
It is here [in your purified heart], brahmin, that you should bathe,
To make yourself a refuge for all beings.
And if you speak no falsehood
Nor work harm for living beings,
Nor take what is offered not,
With faith and free from avarice,
What need for you to go to Gaya?
For any well will be your Gaya.
So, there is no magic bullet, no secret mantra that will free us. We’ve got to go through the challenging process of recognizing what specific patterns of thinking are holding us captive, suppressing our freedom. And then we have to find a way to deal with each one.
If we decide to take it on, if we choose to pursue improving the purity of our own hearts, then we will surely reap the rewards in our everyday experience. Although certain of the imperfections on the list are said to fall away at different stages of mental development, each of us has our own karma, our own strengths and weaknesses. As Ajahn Chah repeatedly said, the defilements arise RIGHT HERE and can only be uprooted RIGHT HERE. So we can start with a constructive attitude: there are imperfections in our minds and with patience and persistence we can identify and wear them away. Our faith is in the fact that a mind free of imperfections is a happier mind.