I loved OG FLCL. I loved that it was basically one big allegory for puberty and growing up, and navigating relationships. The music is amazing of course; The Pillows are an amazing band. I love old japanese rock. Bump of Chicken is another great band in a similar style.
FLCL is the best, about growing up, finding oneself, being true to yourself, influenced me into coming up with my own story. The quirky and eccentric style of animation is exactly why I love anime in general. Swing the Bat!