These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Ashita no Joe
Fair for Its Day: Despite...pretty much everything about Harimao, it should be noted that that the manga portrays all of the other foreign boxers that Joe faces in a positive light. Carlos' style, antics and personality make him a fan favorite among the Japanese crowd, despite some of his off-color comments to Joe, Mendoza never does so to any of the other Japanese characters and is shown to have a human side with his concerns of being around for his family. Even Ryuhi Kin has his admirers despite being a complete asshole, mostly due to his tragic backstory.
It Was His Sled: If you don't know by now, Rikiishi dies from injuries sustained from his match against Joe. Also, Joe dies after his match against Jose Mendoza.
Jerkass Woobie: Ryuhi Kin. On one hand it really sucks to have your mom become a casualty of war in front of your very eyes and accidentally kill your father. But on the other hand, his sordid past clearly gives him a sense of entitlement; it makes him feel that he's better than anyone else in the sport, looks down on boxing as just a game that shouldn't be treated with any passion just because there are rules in the sport, and looks down on Joe especially for struggling with his weight, just because nobody else he knows had to go through what he did. Not a good way to win sympathy points.
Moral Event Horizon: After Joe humiliates Wolf in the locker room brawl, Wolf retaliates by beating up the neighbourhood children that Joe hung out with. Yeah, while Joe was a terrible Jerk Ass to him, it's not like the kids had a lot to do with that.
Tear Jerker: The death of Rikiishi. Joe finding out Carlos has gotten a severe case of brain damage after his fight with Jose. And of course, the entire finale, where Joe dies.
The first one's specially poignant in the anime, because it also included a BIG Hope Spot. Rikishi won fair and square, Joe aknowledged it and wasn't angry at all about that... and when both loser and winner were about to shake hands...BAM. Rikishi's brain damage kicks in, and he simply drops dead. Cue the Pastel-Chalked Freeze Frame and the narrator explaining what was going on.
In the first anime, to add insult to injury, Rikishi falls with his hand still extended.
And about the third one, well...we all know what happened there. Not helped by how right before dying, Joe gives his bloodstained boxing gloves to Youko and tells her to keep them. Soon afterwards, Joe passes away; when Youko realizes that Joe is dead, she drops them in horror, and everyone starts standing up, and then we have THAT image...
Weird Al Effect: Very few western Otaku have ever seen the original series. But the show has been parodied for so long, and by so many creators, if you've watched a lot of anime, you've seen Joe.