I have a few different reasons:
1. The music. Especially the instrumental. It's just....amazing! I was listening to it yesterday, and I could picture almost every scene during it.
2. The movie itself. I love the lessons in it, like how you can't live in the past. You just have to keep moving forward. And it's one of those movies where you could watch it a million times and still not get bored of it.
3. The villains. Scar was a great main villain in the movie. I especially like his son, "Be Prepared". It's in my top 3 favorite villain songs.
And the hyenas are really funny! It's rare that you see a villain that is
purposefully funny.
4. The romance. I have a thing for romance in books/movies. That's why I absolutely
love the song "Can You Feel the Love Tonight?" (except for Timon and Pumbaa's parts in it - although their crying at the end always makes me laugh).
That's all I can think of right now.