Our every thought is a karmic act. If a cause arises from wisdom, so then will the effect. If a cause arises from ignorance, so will the effect. Unfortunately, we plant causes mainly because of our ignorance, and this is why we have created innumerable transgressions in our past and present lifetimes. Most of the time, our bad deeds outweigh our good ones! If our good deeds had exceeded the bad ones, we would have already transcended the cycle of birth and death.
As long as we remain in this cycle, we will undoubtedly commit more bad than good deeds. Thus, we should be very cautious and mindful. Fortunately, as the Buddha tells us, our karma is not fixed and can be transformed. Since everything arises from our minds, our karmas also arise from our minds. Since our wrongdoings are created by our minds, then they can also be transformed by our minds.