As an arcade-loving boy, I grew up stuffing my bills into change machines over and over again, only to have the rolled right back out at me. The charming American affection for paper money and the rising price of soft drinks seems to have driven technological improvements, though. Now I can stick a bill into a vending machine with only, maybe, a 10% failure rate.
I can’t say the same for hotel room key cards and their readers. They seem to have a failure rate of, oh, 66%. That is, when I insert them in the lock or elevator thingie, I get the red light two out of three times.
Maybe I just have some kind of anti-key card aura?