There's no evidence for the existence of karma, so no. Most people who say they believe in it do so because of regular biases like anchoring bias, confirmation bias, availability heuristic, and a whole bunch of other ones.
Just as one example of many, if you do something you percieve as bad, then most people are more wary of potential consequences of their actions, and if you do something you perceive as good you're more likely to seek potential reward to that. When in reality, anything that you may have noticed was more than likely just coincidence that you just wouldn't have paid attention to otherwise.