In 20-ish years, I've "lost"....
- a couple armloads of various cables (xlr, patch, speaker, power...each with a unique story for sure)
- more power strips that I even want to think about (mostly "loaned" out to other people and never returned...people suck!)
- more flashlights than I care to think about (generally left in the DJ booth, and they wander off mid weekend)
- several dozen partially used rolls of gaff tape (these almost certainly grew legs...people suck!)
- a pair of speaker stands in a gig bag (I still have NO idea how I managed to leave without them...but c'est la vie)
- a few CD wallets (I carried a "full load" of CDs until about 2002-ish....almost everything I lost were CD-R's not originals...thankfully)
- a hand truck (this one REALLY hurt - it "wandered off" sometime in the middle of a 6 day event and I did not notice until the loadout on Day 6 - I would up "borrowing" two hotel carts for about 8 hours during the teardown and loadout)
While I would like the list to be shorter....overall, I am not terribly pissed about any of that stuff (except the handtruck....if I ever find that bastard....grrrrrrr). I have never lost any electronics, wireless systems, speakers, laptops, controllers, etc. So, while its still frustrating, it is hardly the end of the world.