Use of Time
The concept of toughness:
Meaning, toughness is, grosso modo, resistance to injury&ability to bitch-slap.
Another meaning is being a thug (which was not the meaning intended here).
And YES, being invulnerable to everything and able to snuff out a species by snapping one's fingers IS toughness. At least by comparison to the snuffed out species.
Snuffing out a cockroack so easily makes you a LOT tougher than the cockroack.
Contrary to the perception in this thread, the concept is far larger than the hollywood image of two alpha males looking cool and trading punches.
Tough - adjective
1. strong and durable; not easily broken or cut.
2. not brittle or tender.
3. difficult to masticate, as food.
4. of viscous consistency, as liquid or semiliquid matter: tough molasses.
5. capable of great endurance; sturdy; hardy
I suppose I'm thinking more of number 5 when I think of humans being tough. They haven't backed down from any of the specied listed above despite being woefully mismatched at times and have even managed to come out on top at times despite the opposition. This is far more impressive than say some single minded drugged up Jem H'dar.