Have you ever seen an anime that you thought was going to be fantastic, but ended up being kind of terrible? Disappointing anime like this appear in every genre, and they can make you regret investing your time and excitement in them in the first place. The feeling can be especially severe when it's a heavily promoted anime that everyone is excited about before it debuts.
What are some anime that didn't live up to the hype? One of the most famous examples is Tokyo Ghoul √A, the second season of a popular show that takes the series in an unwanted direction. In a completely different genre, Glasslip takes a cool premise and turns it into utter nonsense.
This list is entirely subjective. If you see your favorite on here, it's not that it's inherently terrible - it's that there were common expectations for it that weren't met. Vote up the anime that you think could have been much better, and vote down the ones you think are fine the way they are.