The origins of the Karen meme are a bit murky, but it's believed that the trend first started on Reddit around 2017. The name "Karen" was used to describe a specific type of middle-aged, entitled white woman who aggressively demands her own way and throws tantrums when things don't go as she expects.
The name quickly caught on as a way to describe a certain kind of difficult customer or entitled person in real life. The meme gained even more traction around 2018 and 2019, as people began sharing videos and stories of actual "Karen" behavior on social media platforms like Twitter and Facebook.
The rise of social media and the popularity of sharing viral content helped spread the "Karen" meme even further, with people using it as a way to mock and make fun of this type of behavior. It's worth noting that not all middle-aged white women are Karens, and the term has been criticized for being sexist and ageist at times. However, as with many memes, the Karen trend took on a life of its own and became a widely recognized cultural phenomenon.