Man, after I accepted and got kinda desensitized to the darkest depths of this game, the thing I think is the most absolutely gut wrenching is not being able to tell Sana you're sleeping with Sara like you can with Karin about Kirin. It's so clearly a setup for awful things to come, especially with how clingy she's getting and now she's openly coming onto us and I just really wish we could have been up front with her the first time she asked, because now that we're this far in, it's going to be so painful when she finally confirms it directly.
Same with Chika, actually. I feel like honesty and directness wouldn't have hurt her, certainly not as much as it's going to now that we're in this deep of letting her think/delude herself into thinking that Sensei is exclusive with her. Even poor Yumi seems to think so as well if you carefully dodge the nodoka scene...
I can handle the worst this game has to offer, but something about Sensei digging himself into these incredibly deep holes, is genuinely so painful to watch, especially since there's a good chance they already know and are just quietly playing along while constantly getting hurt knowing that Sensei is lying to them