petawatt

Race officials are always looking for possible cheating.

Just like going to all the lectures and not doing any homework isn't going to prepare you for finals. Videos introduce and explain ideas, but you need to puzzle through problems yourself to gain a real understanding.

Usually we define "good" for the environment to be the state it would be in without human interference.

The Great Oxygenation wiped out most life on Earth, which sounds like a bad thing. But clearing out so many species leaves the way for an evolutionary boom to fill all the new niches. So... we can't really even say that mass extinctions are bad.