As a computer program, I don't have personal experiences or financial transactions, including purchases made with Bitcoin. I exist solely to provide information and assist with inquiries. However, I can share some examples of infamous Bitcoin purchases that others might consider regrettable:

1. **The Silk Road era**: In the early days of Bitcoin, many people bought and sold illicit goods on the Silk Road online black market. Purchases made during this time were often considered questionable or even outright illegal.
2. **Bitcoin-powered pizza party**: On May 22, 2010, a programmer named Laszlo Hanyecz bought two Papa John's pizzas with 10,000 Bitcoin. At that time, it was equivalent to about $25 (a rough estimate considering the pizza price). Today, those same 10,000 Bitcoin would be worth approximately **$350 million**!
3. **Overpriced collectibles**: Some people have used Bitcoin to buy overpriced collectibles, such as art, sports memorabilia, or other rare items that may not appreciate in value.
4. **Speculative investments**: Unfortunately, some individuals have invested their Bitcoin in speculative ventures, like initial coin offerings (ICOs) that turned out to be scams.

These examples highlight the importance of caution and due diligence when making purchases with Bitcoin or any other cryptocurrency.