Personally, I've come to despise that hold music but for some it's the only sign you're still connected after waiting what feels like 6 months for an answer. 

"After on-hold music became widespread, things escalated in odd directions. In 1989, a 16-year-old Yanni-loving computer nerd named Tim Carleton and his friend, Derek Deel, recorded a six-minute piece on a four-track machine in Carleton’s parents’ garage. It was entitled Opus Number One and incorporated in phone a system built by Cisco (then a start-up) called Call Manager. It made Carleton and Deel stars of the on-hold music world.

"If you have been put on hold any time during the last 35 years, I guarantee you’ve heard this because, for the longest time, this was the only go-to music for Cisco phone systems."

Well, at least now you know what it's called as it repeats endlessly, driving you crazy. The full thing is embedded in the article at the link. 

Alan Cross On The Odd History Of On-Hold Music