Probably the most annoying thing on a Monday morning, or any morning for that matter, but very useful when you need to wake up early or at a certain time. Usually have very high pitched tones so you will be so annoyed that you'll get out of bed to turn the damn thing off.
Person One: I need to wake up early! I should tell my mom to wake me up.
Person Two: You should just set an alarm clock. It's a more annoying sound which most likely will get you out of bed faster to turn it off.