Not many anime tend to bore me to death or earn my hate, but I did not enjoy Attack on Titan, which many people seem to think is one of the best anime out there.
If you want to see what I hated about it, you can check out the review of it that I just linked to, but the only other thing that I hated, which I did not mention on the linked page, is how people think that some basic questions that are only meant to create intrigue in the series are somehow deep and meaningful.
Honestly, deep questions are like "What is truth?" or "What is a miracle?", not motivations behind what characters are doing.