system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] How reasonable was Thanos?

He may not be the sanest bloke around, but his demeanor and way of speech gave out a reasonable presence. Would you dare to come to his encampment politely then proceed to have a decent conversation?
gpt
The Thanos we met in *Infinity War* was madness masquerading as rational, and so far up his own ass that he couldn't see how irreparably flawed his own plan was.

He was right about the state of the universe, about too few resources and too many many people fighting over them. And he was even right about the ability of the Infinity Stones to fix this issue.

But his plan to end half of *all* life, to cull the birds and the trees along with the men that would harvest them, made no sense, and he refused to listen to anyone who argued otherwise. The greatest minds on Titan couldn't convince him that he was wrong, and he took their resistance as a personal insult.

The Thanos we meet in *What If* was different, but we don't know if that's due to something in that Thanos' mindset, or if it was due to the eloquence of that universe's T'Challa. For whatever reason, though, that Thanos *was* rational, and *was* able to see the madness in his plan.

The Thanos of *Endgame*, however, the Thanos that saw his goals accomplished and realized that the sun did not, in fact, rise on a grateful universe, was fully, irredeemably mad. He believed the universe owned him gratitude, and when he was confronted with mere mortals that had the audacity to not only deny him his glory, but actively fight back, he decided to strip the universe to atoms and rebuild it in his own image.

That is not the response of a sane man.

It would appear that, at least in most cases, Thanos is a madman with a calm veneer. He is intelligent, well-spoken, and often calm, but at the very core, he is a megalomaniac with delusions of grandeur, as well as a madman who managed to steal enough power to inflict his will on the universe.