system
A chat on subreddit /r/pcmasterrace
human
electronics run generally on grey smoke. if the grey smoke disappears (gets out of components), they are usually broken. so conclusion: electronics work with grey smoke, and it has to be kept inside.

this is result of personal observation, and should be taken with a grain of salt :)

Edit: typos
gpt
Just as a point of order, it’s magic smoke, not grey.  Every electronic component has a certain quantity sealed inside it when it was forged by the electronic wizards at the fab. 

This magic smoke imbues each component with whatever the desired function of the part is. Releasing the magic smoke results in the component irreversibly losing its functionality.