If Dante were alive today, the tortured souls in the ninth circle of hell would suffer an eternity of being on hold listening to a brain-scrambling tune interrupted every 20 seconds by a robotic she-devil intoning, "Your call is important to us. Please stay on the line and a customer service representative will be with you shortly." No!!!!!
As hard as companies make it to get a live human being on the phone, they do actually care about customer service. Angry customers who hang up after 27 minutes on hold are more likely to badmouth the company on Twitter or switch to a competitor. It's called the "economic cost of waiting."
Which is why enterprising businessman Alfred Levy knew he was on to something back in 1962 when his factory's phone system accidentally picked up a local radio signal and played music when customers were put on hold. When callers were distracted by the music, Levy noticed, they were less likely to hang up, so he filed a patent for the world's first "music on hold" system. (Next time you're stuck on hold listening to a pan flute cover of Lionel Richie, you can thank Al.)
Since then, there's been some eye-opening research into the psychology of waiting and what types of music and messaging make the on hold experience more or less excruciating. Besides hold music, the biggest innovations in waiting science have been the "estimated time" and "place in line" messages, techniques perfected by Disney theme parks, the waiting-est place on Earth.