One of the uses of Twitter, I've found, is for complaining when there's no one around at the moment to hear your complaints. So you broadcast them on Twitter. And one common activity that results in the "bored and angry" mental state necessary for such tweets is being on hold on the telephone. Here are a few recent tweets in this genre from people I follow.
"I wonder if being used as hold music for a large corporation is good or bad for an artist's career? I'm pretty fed up with this song." (link)
"Conference Call Smooth Jazz makes me want to stab someone. That's a normal reaction, right?" (link)
"Isn't it odd how hold times are so much longer for complaints than with contracting new services?" (link)
"My call is important to them. However, they are currently assisting another customer." (link)
"Telephone hold music makes me stabby." (link)
The similarity between what Jagosaurus said and what BadAstronomer said is pretty funny.