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Real life example. The machine shop of the company where I work has HAAS VF2 milling centers. At 3.5 tons, you'd figure a big enough to warrant some care and respect. 

The favored method of data transfer is USB stick.

On a winter day, the cnc programmer picks up enough static on the short walk from his desk to the machine, that it would discharge upon inserting the USB stick. In the older of the machines (mid 2000's generation), this discharge would sometimes reset the whole thing, as if you flipped the power switch. Ruining whatever was being cut, which could be multiple parts in the setup, and if a skinny drill or tap was engaged at that moment, the sudden stop could break that.

That is the kind of thing the EU's stricter ESD requirements are meant to prevent.