"Imagine there is someone who takes care that your car or machine always works reliably" is for us the most beautiful definition of FuSi.
Functional safety (FuSi) is regulated by the IEC 61508 and ISO 26262 (automotive) standards. Functional Safety is concerned with safeguarding against potential malfunctions of anything with a connector (E/E systems). Functional safety ensures that potential malfunctions do not have a critical effect or, in the best case, that the user does not even notice them. For example, FuSi ensures that the steering in a car does not steer without the driver moving the steering wheel.
FuSi is becoming more and more important with more and more electrical and digital systems. I often hear FuSians (people who do FuSi professionally) say:
"If nobody knows me, I fulfilled my job!"