Stephen Hawking is brilliant.

Don't overuse the word, or you lose the meaning.

It's like 'hero'.

Heroes charge machine-gun nests. Heroes throw themselves on grenades to save their buddies. Heroes run into burning buildings to save people.

When people are called 'hero' for lesser things, it devalues those whose actions are truly heroic.
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She was standin' alone over by the juke box, like she'd something to sell.
I said "baby, what's the goin' price?" She told me to go to hell.

Bon Scott - Shot Down in Flames