This chapter touched my very soul.
I worked in customer-facing call centers for 8 years. The mental pain was unbearable, I felt that 'ear pain' Shima mentioned.
It fundamentally changed me as a person. By the end of my tenure in call centers I had changed from a happy-go-lucky optimist into a pessimistic borderline nihilist.
I don't regret quitting without a plan, and the time I spent away from employment healed me, but even now I still feel the permanent scar of those times.
Sorry to offload that onto a chatroom a manga, but I'll end this by saying: if you are in a call center and feel this way, it doesn't get better, get out before it changes you for the worse.