For many years I worked in the cleaning industry, mostly schools and government buildings, and I can't estimate how many pens we swept up, removed from drains, dislodged from furniture, and otherwise trashed. God knows why they were where they were, but anything that had the misfortune to be lost might also have had the misfortune to be too dirty to reuse. Off to the dumpster they went.

Things that fall on the floor are deliberately or indeliberately kicked under other things or simply away, picked up and kept, etc. Pens especially. Often, people are careless with things they don't value, or aren't their own.

Peace, Mooh.