the way hazel and jason's friendship ended, that's a thing i will hate forever.
the first form of interaction that we have between these two is that the name hazel was one of the five names that jason remembers, isn't that adorable?. a book later we meet hazel and she tells us that jason was the one who integrated her, the one who showed her new rome, the one who made her feel comfortable in this new world completely unknown to her, he was the first person who could consider someone trustworthy (besides nico obviously).
she admired jason and he considers hazel his friend. all of this could have ended in one of the most beautiful and healthy friendships between two teenagers in media. this all changed when jason and percy were swap.
while camp half-blood spent three days without their hero, camp jupiter spent SIX months without theirs. in this time hazel was just with nico, just because nobody wants to be close to a daughter of pluto obviously. then frank arrived, hazel became someone that jason had once been for her, someone friendly. a while later percy arrived, hazel also was friendly with him, this ending of the three went on a mission together. thus making a very strong connection (which ngl was quite ignored by rick in the next books) but still not forgetting about jason, because this girl mentions several times how good jason was.
some time later the seven got together and began their trip, their quest, after many events we arrived at this famous discussion, the said debate between leaving or rescuing nico from that jar.
to refresh your memory, i'll tell you that the person who suggested that nico should be left there to die was not jason, as you all erroneously always mention, it was actually leo, leo fucking valdez, everyone's favorite but frank and piper's hello kitty top's aka me :) when he mentioned this, hazel asked him what the hell he was thinking.
jason, knowing that leo would not know how to explain himself in a good way, decided to speak and take the subject through logic, which actually makes a lot of sense. nico being supposedly part of percy's search team always knew where he was, this boy had previously tried to kill percy before, he asks if he can really trust him knowing this.
honestly, i think they are both right, hazel's reaction was valid, they are accusing the person who rescued her from eternal boredom, her brother, of being a traitor. but on the other hand jason's point is good, are you really going to put in danger the fate of the world for someone you can't trust? nahh he's not going to risk the lives of his friends for someone he doesn't even know. both sides of the argument are valid, that's a fact, so much that everyone thinks about it, even percy himself who has known nico since he was 10 years old god.
all this caused a break in the relationship between hazel and jason. for her he was no longer that kind boy she once knew, no, she sees him as everyone does, as a perfect hero, so perfect that it gives mistrust. he realizes this and is the whole series trying to fix this. which we know very well that he could not do because these two were never like before. this is something very realistic, due to arguments, friendships never return to the way they were before, due to thinking differently than someone else, relationships are broken.
it's very sad, isn't it? i always imagined that these two would have an inej and matthias from soc type relationship, like "you are actually not that bad, i'm your number one fan :)". i always felt like we needed a friendship between the romans, also i always felt that jason would have been very good friends with frank and hazel (i'll talk about frank and jason's relationship in a future post).
the last thing we have of these two is hazel touching his coffin, saying that they and especially piper needed him. i like to think that hazel said this actually because those 6 months he was in new york, thinking she really needed someone like jason in her life.