can i be a hater for a second? can i be a hater and no one gets mad? i have nothing against this person but i think this is a bad take and as #1 gai fan i feel compelled to defend kakashi
the first thing is like... when kakashi was actually mean to gai they were like, twelve if not younger. they were child soldiers, kakashi's dad killed himself, and gai was annoying. i don't think it's unreasonable for a kid, especially one who has already been through what kakashi has been through, to be a little rude to someone who is bothering them. nice? no, but they're twelve. they'll get over it
second is, assuming we're including noncanon material because really that's where kakashi being "sour" to gai happens for the most part, kakashi...isn't really that mean to gai anyway. he's annoyed, sure, but he still humors gai through challenge after challenge, and pretty much instantly backs down on being mean to gai as soon as gai starts crying. i'm not trying to say he's super nice or anything, but he's pretty much baseline cold with everyone, and he absolutely proves himself to have a soft spot for gai. even in the anbu, any time he's been particularly cruel to gai it's very clearly Not About gai, and he apologizes after the mission with the hannya ops for being mean to gai
kakashi absolutely does care about gai as much as gai cares about him. he is cold because he's terrified of losing someone else, and he's trying not to get gai hurt, or get hurt himself. again he was largely a Child. a lot of the meanest things he says to gai are spurred by fear, and he makes up for them as well as he's able to depending on the situation. it might not always be Enough, but that doesn't mean he's not trying.
fourth kakashi might act kind of lame and aloof but it's really clear he takes their rivalry seriously. he puts up an act but he always meets gai on his level, and has a sincere respect for gai as a shinobi and as his friend. the only point in the present timeline when he's really "mean" to gai is during the chunin exams, because gai taught a suicide technique to a thirteen year old. even that he apologizes for, even though what gai did was wrong(!) because he feels bad seeing gai so guilty over what happened to lee.
in shippuden, he even begins to be more sweet and honest like in this scene:
where he outright tells gai how deeply he values and cherishes his presence, and that he hopes they will always be rivals. and this is filler but so is a lot of kakashi's "cruelty" towards gai (not that either is necessarily less valid in their dynamic just that they're on equal standing) and in the 4th war canon kakashi tries to cheer gai up when he starts to feel depressed about being left behind by the new generation, and talks him out of opening the 8th gate the first time. he also sticks beside gai for the entire war, and carries gai when he's unable to walk even when just leaving him to rest might be more efficient. he cares a lot
even the big emotional hit for kakashi in konoha shinden is him admitting he would've just as easily fallen for the cult's trap had they promised him one thing: a way to heal gai's leg. he's been worrying about gai for ten years. he might act a little distant or too-cool, but not once has he ever expressed a disinterest in gai's safety or wellbeing, and in fact most of the time he makes it very clear he cares very deeply for gai. just because he wasn't always able to be there emotionally doesn't mean he didn't give a shit about gai, or that gai's care for him was at all one-sided. it just took kakashi a longer time to be able to express that openly
also i don't mean to imply anything abt anon so i hope this doesn't come off as accusatory but i don't really like the idea that kakashi wasn't worthy of care because of behavior caused by his severe mental illness. sure, i wouldn't have blamed gai for pulling away from kakashi, because kakashi was not always kind to him! but that doesn't mean gai's compassion was misplaced, either. he had the ability to care for kakashi so he did, because he believed the kakashi he loved was under the anbu mask. and kakashi's depression and ptsd don't make him incapable of caring for gai in return, either. he just needed time to come back around, and he might have never made his recovery if not for gai's intervention. that doesn't mean he didn't deserve it
and, finally: thats exactly why i fucking like the ship. gai didn't need to do any of that. he may have never gotten anything out of it. kakashi might have genuinely hated him and never gotten better and never cared about what gai did for him. and gai didn't care. he loved kakashi enough to do it anyway, because he saw a glimmer of the boy he was once so inspired by still in there, and he could not let him die. and through his grueling, painful, sometimes sad, sometimes fruitless efforts, he managed to get kakashi out of anbu, and set him on the path to a brighter future. everyone around them thinks it's one sided and that gai just doesn't realise that kakashi doesn't care, but if you just look a little closer, you can see just how much love and respect kakashi really has for gai. even though they grate on each other sometimes, they both know who they can trust more than anyone in the world. gai absolutely has the self possession and respect not to let himself be walked all over by someone who doesn't really give a shit about him, and that's not kakashi. it's why gai stuck around. it doesn't matter if kakashi "deserves" gai, because gai believes he does. and kakashi, as much as he may sometimes be sarcastic or seem distant, absolutely values what gai has done for him. he just doesn't always say it outright, and gai knows him well enough that he usually doesn't need him to.
tldr i don't think "deserving" is really a meaningful way to assess their relationship, and what makes them interesting is the complexity of how they interact and care for each other in different, sometimes subtle ways. it's really reductive to say kakashi doesn't care or that their relationship isn't mutual just because of previous factors, or kakashi's facade of coolness. i like them a lot sorry anon if you see this you probably dgaf and that is Okay ❤️ i just wanted to talk about them