Here’s one for the annals of Diablo tragedy. A player accidentally sold their 
Harlequin Crest and subsequently blocked themselves out of buying it back.
Odd_Delay_3231 ran into a pretty painful situation. In a perhaps even more painful addition to it all, they also captured it on video! We can see exactly what happened, as they sold the Shako first, and then proceeded to sell all junk items. This pushed the Mythic Unique out of the buyback row, making it gone forever. It wasn’t quite max masterworked, but 8/12 isn’t exactly nothing either!
You can even spot a pause in the process right after they sold the helm. As explained in the comments, Odd_Delay_3231 thought that they had equipped the helm instead of selling it, and then proceeded with the tragic part.
These are definitely the perils of forgetting to favorite your gear, or un-favoriting it. The controller didn’t exactly help either, as it’s much less precise in these matters. And you can see in the thread’s comments that Odd_Delay_3231 is very much aware of the huge mistake, accepting full responsibility and just trying to commiserate with the community.
We’ve all misclicked/pressed at one time or another, but this one is among the most painful out there. So Fs in chat, RIP in peace and all of that. We hope Odd_Delay_3231 can find another Shako soon, however, and we definitely hope they’ll favorite it if they do!