I figured it's time for me to give my opinions on this.
Because a lot of pop music in Japan uses the Royal Road progression, I hear it all the time in anime openings, and it's become equivalent to Four Chord Songs in my brain.
The Royal Road Progression is: IV-V-iii-vi.
And if you ever wanted...
Oooh, as a musician, I love some anime OST's because they're fun and interesting.
Here's a few of my favorites.
"Cruel Angel's Thesis" Neon Genesis Evangelion:
Anyone that's seen Neon Genesis Evangelion knows that it's a very depressing anime, yet the opener is a certified BOP. So happy...