Mt. Gox
The bitcoin blockchain seems to have failed to keep an accurate ledger of who paid/received what from whom. Wasn't that one of the basic ideas of a blockchain? I lost about 10 bitcoins from Mt.Gox a few years back and even with my email address and account number I cannot recover or even file a claim with Mt. Gox anymore. Regardless of the theory behind blockchains, implementation, in reality, is still problematic and maybe it will always be so. The blockchain has lost my trust. It's a far cry from proven versitility of fiat currency.