Michael trolls me in a simple yet effective way:

I've quickly marathoned through sub-par shows in the past. However, good series such as Stand Alone Complex, Tweeny Witches, and Legend of Galactic Heroes can't seem to hook me in like that. All three of these anime are top notch quality, yet none of them have me desperate for more. Wouldn't this mean they aren't all that great? But then why am I having such a hard time criticizing them?

So, what about you? Have you any series that you know to be extraordinary yet you can't quite find yourself compelled to give them the attention they should -- in your mind -- deserve?

OK, I'll bite. But to be clear, I abandoned or otherwise downchecked a whole bunch of shows that someone else liked. The short list of rejects below is only that of titles I consider masterpieces in abstract, or at least credible attempts. The aforementioned GiTS:SAC misses that benchmark, in my opinion. So, sorted by decreased masterpieceness:

Mushishi: Masterpiece? Hell yes. In the same time, the most boring anime I have ever watched. I dragged myself through 10 episodes.

Princess Tutu: A masterpiece indeed. But for some reason I cannot connect with and/or care for the characters.

Dennou Coil: This is what happens when the best talent is given a lot of money and told to manufacture a masterpiece. It's just not the same as the real thing. The dumb nuclear war filler was where I gave up on it.

Aria: This one I have actually completed, but I think I shouldn't have. Completely presses wrong buttons for me, and again, did they have to make Akatsuki such a jerk?

Macross Frontier: Not a masterpiece in an artistic sense, I would say, but a show I would love to love. Sadly, I find it overwrought. But I always boost it if anyone asks.

Hidamari Sketch: As far as slice of life shows go, Hidamari is a masterpiece; a masterpiecer show than Aria. But would it _hurt_ SHAFT to actually animate the blasted thing?!

Twelve Kingdoms: Completely ruined by slavish adherence to the material and thus incomplete storyline (see also: Haruhi Suzumiya, The Melancholy Of). But it does not have to be like that, and Banner of the Stars is the proof.

UPDATE 2010/01/05: Michal gives a second chance and turns for some (e.g. LoGH). For my part, I glanced at the list above, and the book is closed on all except Mac F.