My worst decision was spending 150$ on a 4th generation iPod at the end of 2010 when I knew about $BTC but had many doubts, and also investing 100$ in iforex and losing it that same year. I should have used that 250$ to buy $BTC ....but that didn't happen. Anyway, I got pretty distracted with the iPod that I now use as an alarm clock and I also learned something about forex.