If you remember the series, you'll distinctly remember the last part, because, to me at least, it was the one of the worst endings ever. It begins with Chitanda talking about her career options and how she can't take care of the business so, she's going to try and research new ways to increase the harvest etc. 

Then, Oreki says to her to let him take care of the business side for her. And for that brief moment, I felt happy for him because grom the first episode, he had been slowly captivated by her and it would've been a good ending to show that he fell for her and did something about it.

Yes, he doesn't do anything that takes too much energy, that's his nature. But, throughout the Anime, his character is developed and he does, willingly, do some thing (like going to a library to research out of curiosity) So, it wouldn't have been that wrong to show that he ended up doing something about his attracion towards her.

But, then, we see that it was just Oreki's imagination and he leaves, without saying it. Again, this does fit his initial nature, but, like I said, it wouldn't have been against his nature if he had said it.

And, this leaves a very open ending to the Anime (which I hate) since they just finished high school and even if Oreki managed to resist this time, he might not be able to in the future (because his character does change). Of course, it could also be that Chitanda has to leave the city for education. Frankly speaking, there are a lot of scenarios that could happen. 

But, I, like Sheldon, need closure. I can't stand not knowing the end to something. I can formulate theories, but, I need to know which one of them was right.

Then, I read somewhere that the Anime has actually planned a season 2 but it's been over two years now, and nothing. 

However, the Anime was based on a light novel, which has 5 volumes. And Hyouka only covered 4 volumes. So now, I'm reading the novel and look for a better ending.

All in all though, it was a really good Anime. One of my favourites. Mostly because it wasn't hyped too much and the mystery content was amazingly explained. A must watch for mystery fans.