It's because they're the unsung heroes of the brain!
A: Brain waves are the electrical impulses that make you go from zero to "I'm going to eat an entire pizza" in 5 seconds. They're like the internet of the brain, except not made of memes, unfortunately.
But seriously, they're the reason you can remember where you put your keys, but not why you put them there.
A: Alpha, beta, theta, and delta. It's like the brain's own special brand of alphabet soup. Alpha waves are for relaxation, beta for focus, theta for meditation, and delta for "I'm going to crash the car and drive home from the bar." Don't worry, it's not as bad as it sounds.