I can sit and talk for hours about how intriguing the concepts in Courage are, from the subject matter, to the setting and color palette, that show puts you in a state of surreality and disarray, and then proceed to bombard you with emotion after emotion. Suffice to say, I love it.
At a close second, Mission Hill. I love everything about the show - namely, it's retro, hipster-esque design. Anyone who grew up in the 90's can easily relate to it.
Not the greatest of all time, but two of my personal favorites.[footnote]I'm excluding Eastern anime for the time being, otherwise I would be here for a while.[/footnote]