Stands are physical manifestations of one's spirit, introduced to the JoJo's Bizarre Adventure in part 3, Stardust Crusaders. While they often appear in vaguely humanoid shapes, they come in many iterations, sizes, and power levels, with some being significantly stronger than others.
Unfortunately, many users with amazing Stands have no idea how to properly use their gifts, and as a consequence, they squander much of their potential. To analyze just how badly a Stand might be held back with a lacking user, let's take a look at some of the most promising spiritual manifestations and how they have been poorly utilized.
10 Okuyasu
Okuyasu's "the Hand" allows him to erase anything he can touch, closing the gap between himself and his enemies and even vanishing large objects as if they were never there to begin with. This gave him boundless potential, as noted by his brother, Keicho.
Unfortunately, Okuyasu's lack of imagination limits how far he can take this ability. Despite having one of the most powerful Stands in Diamond Is Unbreakable, Okuyasu's fighting performance leaves much to be desired.
9 Boingo
Technically, Boingo should be nearly invincible. His Stand allows him to predict the future with perfect clairvoyance and guarantee a method of defeating his adversaries through the pages of his book.
However, because Boingo is such an incompetent and cowardly planner, he often relies on the strength and machinations of allies to help see his vision through. These comrades invariably end up harming themselves much more than their intended target, and since Boingo is too spineless to confront his foes on his own, there is no way he can actually capitalize upon what is supposed to be a victory written in fate.
8 Doppio
While Doppio and Diavolo are technically the same person and share a Stand, they are two separate characters on account of their drastically different personalities (further exemplified by the fact that they died at different points in the story).
Though his master may be skilled at using Emperor Crimson, Doppio does not share his proficiency in its usage. Despite being able to view and erase time itself, Doppio suffered a humiliating defeat at the hand of his sworn enemy, Risotto. Were it not for Narancia's unwitting intervention, Doppio would have been murdered on the beach, ending the series before Bucciarati's numbers thinned too grievously.
7 Carne
Carne was one of the least serious threats that Giorno and his allies faced. As he malevolently approached the plane, he was shot dead by Mistah in a matter of seconds.
Much to the young adventurers' surprise, this would not prevent his Stand, Notorious B.I.G, from infiltrating the plane and attacking them. As valiantly as they fought, they could not destroy the creature sustained by pure hatred. Ultimately, they could only hope to escape it, thrusting it into the ocean where it would slowly grow larger over time, an unnatural horror that would prey upon innocent sailors.
6 Dio
Though Dio may have been the hardest fight of Jotaro Kujo's entire life, this was attributed to the immense and insanely overpowered properties of his Stand, rather than any skill of his own. He was constantly outsmarted by the hero, forcing him to overuse the World's ability to even the odds.
Despite being able to freeze time significantly longer than Star Platinum, having an immortal vampire body, and even achieving perfection through absorbing Joseph Joestar's blood, Dio could not overcome his youthful opponent and would lose what should have been one of the most lopsided fights in the series.
5 Shigechi
Shigechi's "Harvest" Stand allowed him to deploy hundreds of tiny minions, each with razor-sharp beaks which could shred the skin and bone of those who would oppose his avaricious ambitions.
When he had the misfortune of running into Yoshikage Kira, Shigechi was nonetheless able to smother him in his Stand and lock him in a death grip. However, because he hesitated, the serial killer was able to break free of his predicament and end the young boy's life. In more capable hands, Harvest would have been more than a match for Deadly Queen.
4 Masazo
Masazo is a particularly unusual Stand user because while he himself is weak, his Stand is arguably one of the most serious threats not only in Diamond Is Unbreakable but in the series as a whole.
Cheap Trick is more than able to destroy anyone whose back is seen; damage it takes is reflected on its user (since it claims whoever is attached to it by default). This spells that the only way to remove it is through the haunted alleyway inhabited by Reimi Sugimoto.
3 Alessi
Alessi's "Sethan" Stand allowed him to reverse the aging of anyone caught in his shadow. In a fraction of a second, he could transform Polnareff from a fully grown man into a helpless child, and after a few moments of concentrated exposure, a woman was reverted into a fetus.
Despite this incredible and horrifying ability, Alessi could not actually defeat the children once they had transformed. His uselessness in battle considerably detracts from the viability of his Stand, especially since Jotaro Kujo was able to pummel him senseless even without the awe-inspiring strength of Star Platinum to call upon.
2 Mannish Boy
Mannish Boy's "Death Thirteen" Stand could whisk anyone sleeping near him into a dream world where the damage they sustained would also impact their real bodies. Further, they would forget what they had seen once they woke up, giving him a number of chances to kill his foes.
However, Kakyoin and Polnareff were able to escape Mannish Boy's clutches on more than one occasion. Were he more interested in flagrantly murdering them than striking fear into their hearts, Mannish Boy may have been able to find more success before the emerald crusader caught on and exposed him.
1 Anjuro Katagiri
Anjuro Katagiri's Stand was able to possess other bodies of water and crawl into its victims, destroying them from within. This made him a proficient serial killer and an excellent distraction for Yoshikage Kira. His crimes also resulted in the death of Josuke's grandfather, Ryohei Higashikata.
However, Katagiri was not able to navigate his Stand effectively, and as a result, his water was captured in a bag, subsequently rendering him Josuke's prisoner. Should he have had better reflexes and higher competence, Katagiri could have made for a more recurring threat.