Stuck on hold
Being stuck listening to hold music for an extended period is annoying. What’s even more annoying for me is when the IVR system regularly interrupts the hold music with a voice announcement, often telling you something enormously useful like pointing out that you’re on hold. Music I find easy to zone out without paying too much attention to but whenever you get a voice announcement it demands a bit more attention – at least until you’ve worked out that it’s not actually a human yet.