It sounds like the system does not obey.
When someone reaches out to you for something important.
That's how Q.E.D. sounds (latin phrase "quod erat demonstrandum", meaning "thus it has been...
This is not the easiest sound to describe.
That feeling when your calculation checks out (picture the "Success Kid" meme).
Closing line of the 'We wish you a Merry Cristmas' song, great as a message tone, notification sound or subtle...
A provoking and perhaps even exasperating little sound.
A call that suggests concealed intentions.
For real, it is exactly as I described it. Yep, it is.