I know this is kind of a soft question, but I'm curious about the hardest search everyone has had. I know I remember mine clearly, though there are close finishers in the "hardest search" category.
Mine was actually a mid-mount ethernet jack, SMJ401-S88W. I designed it in after digikey carried it and it perfectly fit my application. It fit into a tight space in the plastic and we designed our molds around it (whoops). As soon as we got our first shots back from the mold house, I got the notice that the part was going obsolete. Holy crap.
Looking around, it quickly became apparent that I didn't know what search term to look for. Sure, I knew that Digikey/Sullins called it mid-mount but that only works if everyone calls it mid-mount. I tried every single combination of "low profile" "board edge" "no magnetics" out there, it just didn't go well for me. I ended up resorting to searching "RJ45" and scrolling through page after page of Google image search, desperately trying to find a new connector.
The solution? I called the company that made them and begged them not to shut down the production line. Luckily I was working at a big enough company that they agreed (it was a good business decision).
Obviously our connector search still needs a lot of work, but the above story will help inform how we design it so that users can try and find what they need. We'd love to hear some of your stories in order to craft a search experience that causes you less stress in your every day electronics design.
ps. The moral of the story is to second source your connectors before getting molds made. Duh, Chris.