Clarence: Fans either think that he's an adorable and funny Cloudcuckoolander, or find his actions not funny at all. In fact, many grew tired of his over-exaggerated Karma Houdini status considering whenever he caused or gotten involved into trouble, he'll more often than not get away scot-free without facing any real consequences or sort of punishment, regardless if he is or isn’t aware of his surroundings. For some detractors it’s to the point where they wished that something particularly detrimental happened to Clarence — even to the point of suffering — just so that he gets even with his more worse actions. Others just wished that he wasn't mandatorily crammed in every episode, especially within episodes focusing on other characters. However, it must be pointed out that he often got flak from other characters in the show for his more annoying actions even if he wasn’t necessarily punished for them. Even then, though, this wasn’t enough to offset his increasingly flanderized characterization as a mindless troublemaker who too often puts others in harm's way. The episode "Dare Day" is a noteworthy example of this, where he and Sumo almost killed each other over a bunch of dares.
Jeff: Fans love him for being an adorkable character with common sense and humor to boot. Others hate him due to his (often over dramatic and frankly uncalled for) freak-outs, his creepy opinions of girls, his It's All About Me behavior, and his obsession with social ranking. He is especially irksome when he becomes hyper-competent in trying to be better than others, particularly towards his two friends, in terms of intelligence and social standing.
Sumo: His fans consider him as the Only Sane Man who is at least more favorable than his two friends (arguing that Clarence becomes excessively stupid over on, and Jeff is no more than a self-centered, egotistic asshole). They further insist that his more negative behavior is comparatively more understandable than, say, Jeff’s, as a result of his poverty-level living standards and overcrowded family unit. The show makes it clear that his parents are overwhelmed with their own jobs and many children, so Sumo hardly gets shared moments with them despite them doing their best for their kids. Also, before making up in “Stump Brothers”, Sumo’s eldest brother seemingly acted like an unsympathetic Big Brother Bully throughout Sumo’s life. However, with all that said, Sumo’s detractors find him just unappealing entirely, others are simply turned off by his rather raspy voice, or they mainly dislike his mischievous behavior, particularly when adhering to Clarence’s own chaotic shenanigans.
Belson: His fans find him funny for being the Comically Serious, and believe him to be a harmless Jerkass Woobie and Butt-Monkey; his detractors hate him for being a rich, Spoiled Brat with borderline Faux Affably Evil elements who deserves his Butt-Monkey status; and then there are those who sum him up as the Clarence version of Eric Cartman, but without Cartman’s charisma and darkly humorous personality.
Joshua: While he has more fans than haters, his fans cannot find any reason to hate him as a consequence of his status as the show’s ultimate Butt-Monkey — even Belson never suffered as much as he did! In fact, while his earlier punishments were minor Laser-Guided Karma, he was increasingly degraded into a Cosmic Plaything and further into Kafka Komedy territory as the show went on, with nearly every entity the series has to offer (special mention towards Clarence and Sumo) seemingly out to harm him in numerous ways. Other fans of the show, however, seem to find no problem with his abysmal treatment and find it rather amusing as the show intended.
