Strangers who have no problem with handing over their documented secrets make me laugh. It never fails that daily, people leave behind IDs, reports, love letters and personal secrets in the machines.
Every so often a friendly older man would come in, we would exchange the courteous retail smile and move along. One day he forgot a stack of his paperwork. I never knew his name so I figured something in the stack would tell me who he was so I could set it aside for him. Turns out the guy taught karate, has a family, kids and is a convicted pedophile. His stack was a mixture of work related documents, church documents and certificates from the church stating he's now "cured." The cured karate man called shortly after asking if anyone left a stack of paperwork in one the machines, he came in later that day and never showed his face again.
Sometimes I wonder how many other creeps I've encountered but then it quickly washes away when I discover puppy photos in the machine.