Tear Jerker / Gate Keepers 21

• Episode 1: Ayane's rather dismissive attitude towards Miu throughout the episode. Which persists to the end of the episode. After the Invader had been destroyed, thanks to the fake-gates that Miu had put into position (even though Ayame's instructions had been extremely vague). Miu asking Ayane if she had done well, being cruelly shut down as Ayane "correcting" her. Explaining that the poor girl had done "nothing", while Ayane had done all the "real" work. Leaving the poor Miu alone and confused afterwards.
• Episode 4: Ayane visiting Miu at her place of work... just so she can criticize the other girl. Even going so far as to accuse Miu of being friendly, only as a front to hide her true selfishness.
• Episode 5: Watching most of the city's non-Gatekeeper inhabitants begin transforming into Invaders. This includes Miu's friends, Chinami and Nao, who we got to know throughout the OVA. They slowly transform while steadily advancing on Miu, who has zero desire to try and fend them off; then she has to watch as Satoka slays them in order to save her, leaving nothing but their crystals. Frankly, it's amazing that Miu didn't end up a bawling mess on the floor after that - though she does stay quiet for a long while afterward, her friends' crystals cradled tenderly in her hands...
• Episode 6: Yukino's death, and Miu's heartbroken tears afterwards.