system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel Cinematic Universe] Why does Tony Stark insist on fighting some opponents in hand-to-hand?

Two instances leap to mind where using repulsors would have been the wiser choice.  When he fought Thor, it was rather obvious that Thor was a better melee fighter, and yet he chose not to get distance.  Of course, given that Thor has Mjolnir, distance might not have helped, but the question remains.

On the other hand, in his fight against Aldrich Killian, he kept engaging him up close, when repulsors would have worked quite well against him.  With no movement powers and no long-range attacks, shouldn't Tony have just picked Killian off at range?
gpt
First, Stark didn't know much about Thor. Keep in mind that the only intel on Thor was from SHIELD and it was based on a very brief encounter with him in New Mexico. *Most* of their information was from his penetration of the SHIELD facility set up to study Mjolnir, and Coulson thought Thor was just a badass human, not a super. Even after the Destroyer came and Thor regained his powers, the only thing humans saw was that he smashed it with his hammer and then flew away. If anything, that just makes Thor look like a Norse Iron Man, not a god.

I think Tony's reaction when Thor crushes his suit *with one hand* shows how little he and SHIELD understood about Thor's capabilities. 

Another factor is that Iron Man generally has only limited ranged powers. Bullets, missiles, lasers, and repulsors are his repertoire. The lasers are limited energy *and* burn themselves out. He only has a few missiles. Bullets are pretty weak, and his repulsors have a rather short range. 

Also, he's not an experienced fighter. He had killed a few terrorists, then fought Stane (an even less experienced man), then blew up some Hammeroids. In fact, his only formal combat training is boxing, courtesy of Happy Hogan.