When you're on hold waiting to check the status of your passport application, there is no hold music. Which is fine, I’m sure it would be something hideously annoying if they did have hold music; it’s just a little disconcerting, because there are long periods of silence where you start to wonder if you’ve accidentally been disconnected.
That's probably why a recording comes on every three minutes or so and says, "Thank you for holding. Your call is important to us. [Kind of like my passport application is important to you? Thanks, that's very reassuring.] All representatives are still busy. Due to high call volume, your call will be answered in greater than five minutes. [Yeah, I kind of figured it would be more than five minutes.] In order to avoid extended hold time, please visit our website at travel.state.gov/passport_services.html. The passport website contains information on how to contact us using email as well. The national passport information center is staffed from 7 am to midnight Eastern time, Monday through Friday, for your convenience. If you wish to continue holding, a representative will be with you."
Usually I'm very suspicious when someone says that something is "for my convenience" - it generally means they're going to be downloading adware onto my computer without asking me first - but those hours are actually quite convenient. The estimated amount of time until your call gets answered never changes - it just keeps saying "greater than five minutes" until the last couple of times, when it says "We estimate your call will be answered in three to five minutes" instead.