The Case for Karma Karma is interesting concept, and same idea can be found in various religions, like in Christianity as form of "golden rule" (Matt. 7:12). Also in major philosophical theories, such as Kant's conception of categorical imperative.
Bad sides about karma belief is that, in Hinduism/Buddhism it evolves conception of past,current, and future lives. Lots people in Asia are being marginalized, because they are believed to collect bad karma in previous lives, and as result to born human. In general human is very low position to be in rebirth system, what means you gathered up lot bad karma in your previous lives, and did various of bad things, and resulted you born into human form. Unless you were born as rich man, prince, or big leader, that indicates you lived good life in past, what will get you lots respect, including Gurus, Bodhisattva's. But if you are being born into marginalized group, like poor, disable, that indicates you have lived bad previous lives. And people make conception of you based on social group you are in, and assume that you gathered bad karma to be born in low class, what can be used as a tool to marginalization, and mainly lower classes suffers from this.
So karma thinking can lead into dangerous ideas.