system
Given the following post, respond as if you're commenting on Reddit:
human
[Doctor Who] I've heard that an evil Doctor would be way more terrifying than the Master. Is this true? And if so, what does the Doctor have that the Master lacks?

The Doctor holds back... a LOT! But the Master is no slouch, either. And yet, I've heard that an evil Doctor would be far more terrifying than the Master. 

Why? Is it intelligence? Resourcefullness? Willpower? All of the above (and more)?
gpt
Ironically? Unlike the Master, the Doctor is good, sane person.

For all their power and genius, ultimately all The Master's plans are basically more complex variants on "show up in a place and stab people until someone stops them". They don't really have any ambitions beyond wandering around the cosmos ruining people's lives at random- they're basically just that bedwetting kid who tortures animals but a genius with supertech.

But the doctor *cares*. They're not just at this for the fun of it like the master, they're not a mad child throwing a cosmic temper tantrum. They're *dedicated,* they have a *purpose.* They want to make the universe a better place and will do anything to accomplish that. And there's little more dangerous then someone who thinks that hurting you is their sacred duty to the world.

It's the difference between the serial killer and the terrorist leader. The serial killer can do a lot of damage, but ultimately they're just a broken person lashing out and they lack the ability to do much more then gut people in dark alleyways. The terrorist leader, meanwhile, is sane and rational. They think that they're making the world a better place, fighting the good fight against malicious enemies, and that allows them to leap to a whole new level of threat.