one thing about doflamingo is that he is a psycho. his heart is frozen solid. he does not have a care in the world.
and his outfit betrays this. because he dresses like a fucking freak. he dresses...carelessly. he dresses like he doesn't care about anything except himself, because he does. but interestingly the most proper we see him dress is ..."when he kills?" no idiot. he's killing all the time. it's when he gets betrayed.
i genuinely believe corazon's betrayal came out of nowhere for doflamingo. he was an absolute blind spot he didn't know he had. and i think the moment he realized he was being betrayed was when he realized tsuru wasn't following them anymore since corazon left the ship. it's the first time doflamingo calls corazon since he first left.
and he was fucking furious! when he calls corazon he is grinning like a fucking maniac. the betrayal doesn't make him sad, it pisses him off. he's so self-centered and obsessed with revenge and violence that it doesn't even occur to him to consider rosinante's angle. a man who is at his heart just a quiet and clumsy little boy trying to get his brother in trouble so no one gets hurt any more.
but there's also another angle on doflamingo's wardrobe. some dork on reddit pointed out that the straw hats all dress very grown up (suits, moustache disguises) when they go to dressrosa, while the donquixote family all dress/are childish in some way. senor pink in his stupid ass bonnet, trebol's snotty nose and the way he fucking talks, dellinger wearing giolla's heels, lao g's bunny hood and spandex, diamante's compliment fishing
doflamingo is a fucking babyyyyy. and he'll never understand why trapping a bird in a cage isn't the same as real love. because power and control have altered his psyche irreparably. he lives and breathes blood. he believes he is a god and humans were put on earth as flesh to serve him. and to do with as he pleases.
he's cold as fuck. by the time doflamingo calls corazon and mentions they got their hands on the op op fruit, and are going to feed it to him, doflamingo already figured out that corazon was a marine spy. he's threatening him. with death!!!!!!!! that's why doflamingo wanted the op op fruit in the first place! for eternal life! he's definitely got all sorts of underling weirdos who would die to make him immortal, but he's saying to corazon, we're gonna make you choke on that fruit and your soul is the one i'm going to stomp on to become immortal.
and to what end! to prove to corazon that burning the world down is the correct way to react to what happened to them? they're both incredibly traumatized- doflamingo is still having FRESH nightmares at age 26. corazon must be too. they're both seen heavily drinking in law's backstory. they're both frantically stuck in their trauma, trying to find some way to defeat it and make everything right, and they both have the drastic and deranged solutions of scared children.
corazon was scarred all over his body, but doflamingo was shot in the eyeball with an arrow. his vision was irreparably altered. he is incapable of seeing the world normally. he was hurt so drastically and horribly that he will never be able to feel hope or peace. he just hates.
there's nothing behind his sunglasses except rage. it's this fire that he kept fueling and fueling thinking he could fight another fire with. but instead he's just turned his own soul into hell.
he dresses so properly when corazon betrays him and he kills him because he's at his weakest. just for a moment, he thought he had someone who understood him, and was there with him through his trauma, and was willing to follow his plan to burn down the world as revenge. corazon absolutely had every opportunity to kill him, in silence, if he had the balls. and that makes doflamingo INCREDIBLY pissed at himself for being that vulnerable.
after all, he has to be alive to prove that what he's doing is right. he can't let himself think for a minute that what he's doing is wrong. he can't allow himself to, because homing believed everyone was human and human suffering was wrong, and homing was the reason he was shot and nearly burned to death and his mom died horribly of starvation and he and his brother starved and got tortured.
he puts the suit on because he needs to be in control. he needs to be in charge. he's wearing gloves, like he's removed from the personal nature of the situation. he needs to prove that he's in this for the blood, and to put a bullet in any doubts.
i could talk about this guy for fucking forever. he sucks so bad. he is a monster, and it's terrifying that he exists. his psyche is broken and there's no saving him. he is truly the only sort of absolute psycho that could enslave thousands (and have all their sense of feeling in their body removed and their families/friends' memories of them wiped) and sit on top of the mountain sipping martinis and smiling.
his wardrobe is so important to him as a character. he looks like this jagged, flaming, swaggering mess of blood and fire with demon eyes. he looks so good. he is so fucking awesome.