Man, Kare Kano really surprised me. I finally finished the final volume and I want MORE!
GAINAX first got its hooks into me with FLCL. After a little research, I heard they also made Kare Kano which I decided to try. With Hideaki Anno at the helm, these characters are well-defined and development is solid throughout. The whole concept of masks and true self are key to finding out about the two main characters Yukino and Arima. Add a cast of classmates, family, and others and you have a group that really begin to grow on you as the series progresses.
I definitely think the characters help make this one so enjoyable: from the determined Yukino, all-around good guy Arima, ultra smooth Asaba (BAAAAA!), the young but wise Kano, the manic munching ultra-kawaii gal Tsubasa (voiced by Mayumi Shintani who also was Haruko in "FLCL" - an anime MUST see), PERO PERO, Yukino's dad who's great for laughs, and many more. Kare Kano has a great (and effective) musical score and I dare you to try and get the opening theme out of your head!
This one has a little bit of everything and you might even learn a thing or two!