One way to hold this word: picture a dial inside each person that shows how strongly they are reacting right now. Some people's needles barely move; other people's needles jump to the top over a dropped cup. Temperamental is a word about that dial. Pointed at the dial itself it is neutral — temperamental differences just means two people's dials are set differently. Said about a person on their own, it means the needle jumps too easily, and it sounds like a complaint. Machines have no dial at all, so calling one temperamental is a borrowed picture: it behaves as if it had moods.
From the word’s history
Wiktionary records the word as temperament + -al, that is, "to do with temperament". That matches the sense that sits closest to the root: the emotional side of a character.
Wiktionary 記錄這個字是 temperament（性情）加上 -al（…的），字面就是「跟性情有關的」。這條線索正好落在最貼近字根的那個意思：性情這個面向。
Wiktionary entry for temperamental, supplied in this packet (source_ref kaikki:3f6f69a190036ae4:992822821:8556), etymology_text: "From temperament + -al."
登入就可以看每一支怎麼連回核心畫面。