Prabhupāda: good karma means performance of the yajñas as they are prescribed in the Vedic literature. And this purpose of this yajña is to satisfy the Supreme Lord. Just like good citizen means one who satisfies the government. Law-abiding. Good citizen. Similarly, good karma means who satisfies Lord Viṣṇu, the Supreme Lord.
Unfortunately, the modern civilization, they do not know what is the Supreme Personality of Godhead, and what to speak of satisfying Him. They do not know. They are simply busy in material activities. Therefore, all of them are doing only bad karma, and therefore they are suffering. They are blind men and leading some other blind men. And both of them are expanding the path to hell by bad karma.
Bad karma, you suffer. That is very easy to understand. If you do something criminal, you'll suffer. If you do something benevolent for the state, for the people, then you are rewarded, you are recognized, you are given title. Sometimes shot. This is good and bad karma. So . . . (microphone sound) . . . some material happiness, and bad karma means you suffer from material distress. By good karma you get birth in good family, janma. You get riches, good money. Then you become learned scholar, you become beautiful also.
(aside) Sit down. There is some trouble with your leg? What is that?
Devotee: There is an infection in this ankle.