For a few reasons:
1. Good catchy openings. I mean Rock City Boy is my jam man.

[There should be a GIF or video here. Update the app now to see it.]

2. Crazy random things happening. Who doesn't an anime with a bit of crazy?!?

3. IM A BIG FAN OF SHIPS!!!

4. Last but not least THE DIFFERENT TYPES OF MAGIC!!!

^FAIRY LAW!!!^

^SKY DRAGON ROOOOAR^

^What happens when you make Mira mad^