These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Crowning Moment of Heartwarming: The final story arc, in which Haruko and her little girl were closer to each other for one summer than most mother and daughter will be in a lifetime, culminating with Misuzu's heartfelt farewell for her.In particular, when Misuzu shouts "Mama" as she regains her memories.
Darkness-Induced Audience Apathy: The monks who cursed Kanna got away with it and caused Misuzu to break down whenever she gets close to someone, no one manages to break the curse, and at the end, Misuzu dies. Many detractors from Air will say that nothing ever happens in the entire series.
Harsher in Hindsight: On June 9, 2011, , the voice actress for Misuzu, passed away from ovarian cancer, therefore making it even harder to watch the final episodes.
It Was His Sled: Anyone even remotely familiar with AIR will tell you that Misuzu dies. Especially its haters.
Jumping the Shark: After Yukito turned into a crow, more than one viewer began to lose interest.
Moral Event Horizon: The Buddhist Monks crossed this line when they placed a curse on the Kannabi No Mikoto that extends to the next lives which is pretty much "If you fall in love, you die". Because she left the temple she was supposed to guard just so she can see her mother.
Oh, and killing her to top it off as well.
You know that tearjerker below? They caused that. That's how far they went with just one action a thousand years in the past.