That time I thought I pushed unwanted changes to 34,000 customers on a client's CRM using their API. Oh wait, that was today! Luckily I didn't, it's just that the CRM's GUI only displays a "no results for search" popup for a few seconds and displays all results by default until the search displays new ones. Thus, I thought the search result was severe thousand entries long by the time I alt-tabbed back.