What investment decision looked smart on paper but turned out to be a bad move for you?

I’ve noticed that a lot of investment ideas sound great when you read about them online or see people discussing returns, trends, or long-term potential. But in reality, things often play out very differently once emotions, timing, market conditions, or personal situations come into the picture. Curious to hear from people here what’s one investment decision you genuinely believed was a smart move at the time, but later realised was a mistake? What did you learn from it? submitted by /u/Product_