Three days ago I finished proofreading a 530-page book. Before shipping it back to the publisher, I thought, "I should make a copy of this in case it gets lost in the mail so I won't have to re-do three weeks' worth of work. Naw, that'll cost like forty bucks. UPS is great--they never lose anything."
I just checked the tracking info to make sure it arrived safe and sound. The UPS website said, "Tracking number not found. We have no record of receiving this package."
Oh dear God.