Morning meeting. Manager, gravely: "昨日、クレームが1件ありました。"
Foreign employee's brain: a legal claim? A warranty issue? Are we being sued?
Reality: a man was upset that his bento had too much rice.
English "claim" is neutral — you claim expenses, you claim a prize. Japanese クレーム kept only the sense of a customer complaint, and hardened it: it now implies anger, and usually implies the complainer is being unreasonable.
Around it has grown an entire professional vocabulary. クレーム対応 (kureemu taiou) is complaint handling, a real job skill listed on real CVs. クレーマー (kureemaa) is a habitual complainer — and the delightful モンスタークレーマー is the escalated version, the one who returns.
This connects to something bigger: 客は神様です, "the customer is a god", a phrase originally from a 1960s singer talking about his audience, which Japanese retail took extremely literally for fifty years. The result is service standards that astonish visitors, and a workforce that has to be trained to survive the deity.
You will hear that Japanese customer service is the best in the world, and it is. What is less advertised is the price: the same system that produces the bowing, the wrapping and the sprinting to fetch your umbrella also produces an entire industry of complaint-absorption, and a word specifically for the customers who abuse it. Both facts are the same fact.