I regret the investment I have in our farm. I invested all of my money into onion plantation. The failure was not in the produce but in the price of onion after the harvest.I haven't made many high risk like investments in my life. I have done a few, but it's only when I knew it was something I felt comfortable investing in. I do a lot of research and take my time with it. I never rush when it comes to investing.
But... Around 10 years or so ago. I invested $5000 of what I had made on a recent temp job, into starting this new business. I don't want to go into detail about the service, as I still may try to invest into the idea again. But, I'm sure you guessed right by this point, but that $5000 was gone, I made no return on the investment and was out of everything. I had like a couple hundred to my name after that. This of course was when I kind of started working, and making good money.
It was a major blow, but I thankfully recovered. I still feel like crap every time I think of it. But I have to remind myself, because I never want to repeat that mistake again.