It's probably the scariest thing mentally for me:
I'll be sitting in my room, typing away on a document. I'm listening to music at a very low volume. It's low enough to where I could hear the clacks of my fingers hitting the keys. It's also low enough to where my imagination starts amplifying creaks around my house. For example, I'll be sitting there, thinking on a tangent and a small movement of the floorboards on the staircase sound like footsteps.
That's not the part that creeps me out.
My computer lags for a second, and a split second later (a trigger of a thousand neurons all at once) two people are shouting right in my ears.
I know this is rare, since it only happens when my mind is purely in a work-mode. It's also a trigger of my ADD, giving me no satisfaction in an ambient workplace. As a result, working with music's practically impossible. I've learned to deal with it, recently.
But still, it happens in real life, too. When two people raise their voice or yell in my ears, I shut off mentally. It's as if I exhibit a strange, sporadic slideshow of creepy faces, red burning people and childhood nightmares.
Sometimes this happens as well:
I'll be sitting down, looking intently at something (much like me typing away on a document). Then, out of the corner of my sight, I'll see two bright yellow lights. I'll look up and my imagination draws out a mirror image a person staring back at me. This doesn't creep me out as much as it would as a kid, mainly because I know what's there physically. Say I'm in a new environment, however - one of which I know is less secure and sound in my mind. My mental thought diminishes. My eyes begin moving around to absorb more light through the peripherals.
Perhaps it's normal human psyche. But regardless, when I get spooked like that, the music I'm listening to goes completely mute.