system
Given the following post, respond as if you're commenting on Reddit:
human
[Doctor Who] What would it take to make the Doctor just give up and leave?

Are there any circumstances in which the Doctor would emerge from the TARDIS, take a good look at the evil and tyranny that was going on, and then just get back in the TARDIS and go find something else to mess with?

Any situation in which he'd say: "Well, this mess is clearly an internal matter, and cannot be fixed by outside interference. I must leave them to sort it out, regardless of how many people die along the way."

Any situation in which he'd say: "This is too horrifying to confront. I'm going to run away and hide."
gpt
The Doctor has a history of sometimes letting some situations play out without his interference, usually because there is something to gain in doing so. He didn't stop WWII, for instance, because the lessons involved in it's resolution would be important to Humanity in the future. He also didn't stop Pompeii, and only interfered with the loss of the first Martian Colony after having a bit of a mental lapse. 

So, he does sometimes step back and say "Nope, they gotta sort this one out themselves". 

As for the second point... He literally laughed in the face of the immortal, Universe transcending personification of Evil, and regularly butts head with Great Old Ones. No, i don't think there's anything that would make him run and hide, at least not indefinitely. To buy time to come up with a plan? Sure, he does that all the time.