The instance where you turn on music/video/etc on a mac computer while you're at class/work/in public and realize how loud it is when you first press play. Immediately following is the "Panic Beeps" where you slam the volume key numerous times to lower it before you offend someone/get caught.
*class in progress*
Girl: (thinks: Ooh! New Katy Perry song! Must listen!)
Mac: CALIFORNIA GI-
Mac: BEEP BEEP BEEp BEep Beep beep beep!
Girl: (thinks: fucking Panic Beeps made it worse...)