FLCL is so worth a watch, if you're at all interested you'd be doing yourself a favor to check it out. It's got feels, it's got heart, it's got a moving and rockin' score by band The Pillows. It's not about some kind of weirdness value like you're maybe thinking, it's a unique work of art that just might click with you.
FLCL is a coming of age story that immerses us in the topsy turvy world of a teenage lad. And does it better than most movies or shows I've seen trying to tackle it, at least for me. It tackles that awkwardness and sadness with a sense of fun and adventure, among many other great things about FLCL.
One of my favorites, and really just thinking about it is moving to me, I think FLCL will stand the test of time very well.