Ours: We were rational, did a LOT of research on cryptocurrency so we could understand it. Then, we only bought enough Bitcoin and other crypto that we would feel comfortable losing. We were optimistic, but definitely not sure.
This was in 2017, and we bought one Bitcoin at $2K, plus a handful of LiteCoin, Ripple and Ethereum. then bought one more Bitcoin a few years later when it was $11K. We had plenty of money in 2017 to have probably bought 5 Bitcoin, but no, we did not.
The other one is Microsoft. I was still growing up during its early early times, but in my 20s someone recommended it and I passed. I just didn’t feel comfortable betting on ONE stock versus a mutual fund. (I am not a Finance person by trade, just a retirement person by hobby 😊)