In Disney’s 1992 classic Aladdin ((Which, by the way, is the only source this post references. I haven’t seen the 1994 direct-to-video sequel or the spin-off TV series, and I don’t intend to.)), Robin Williams’ Genie can do pretty much anything – except, as he points out shortly after meeting the eponymous hottie, grant more than three wishes, kill people, or force them to fall in love. Those exceptions aside, his powers are pretty much limitless.
(Or are they? What would happen if Aladdin wished that the rule banning wishing for more wishes no longer applied? Surely Genie would have to grant it; that Aladdin can wish Genie free at the end of the film demonstrates that it’s possible for “commanders” to wish genies to overcome their limitations.)
So, on the face of it, it makes sense for the archvillain Jafar to wish to become the most powerful genie in the film’s climax. He thereby gains that limitless (for all intents and purposes) power. “Ah ha!” you might point out. “It’s actually stupid of Jafar to wish to become a genie, because genies can only wield the full extent of their powers when a commander wishes for them to do so!”
But we know this isn’t so: when Aladdin is trapped with Genie in the Cave of Wonders, he tricks Genie into freeing him without wasting a wish. This proves that, in the Aladdinverse, genies can use their powers under their own steam. They may not like doing so – even when Aladdin is unconscious and drowning, Genie doesn’t save him until Aladdin kind-of-but-not-really “wishes” to be saved – but there doesn’t seem to be any penalty for granting these “freebies”.
(If you wanted to fanwank a little, and I do, you could make out like there’s some “genie equivalence rule” which dictates that, since Aladdin scored a free wish from Genie, Genie is thereby obliged to “trick” Aladdin into making a wish – which he clearly does in the above scene, by almost literally putting the words of the wish into his mouth.)
However. Further analysis reveals that your initial impulse to believe Jafar is stupid is correct, albeit not for the reason you supposed. It is stupid of Jafar to wish to become the most powerful genie in the world – because he had already wished to become the most powerful sorcerer in the world, which is already powerful enough.
(Jafar’s first wish to become sultan of Agrabah was a total wash, by the way. First, why not just wish to become ruler of the whole world? Granted, we don’t know big Agrabah’s empire is, but it’s sensible to cover one’s bases. Second, why not just wish to become a sorcerer in the first place, then use all that sorcery to usurp the Sultan?)
It’s telling that, after Jafar becomes the most powerful sorcerer, one of his first acts is to strip Prince Ali of his ersatz royalty and transform him back into plain old Aladdin. In other words, Jafar undoes the effects of Aladdin’s first wish. In other words, he overcomes Genie’s powers. In other words, at this point of the story Jafar is at least as strong as, if not stronger than, Genie.
The fact that Jafar – who is ostensibly a clever man, having managed to rise to the position of Grand Vizier in the Sultan’s palace, though in hindsight he probably only managed that because he had that hypnosis-snake-stick-thing – is then stupid enough to allow some riff-raff street rat to trick him into eternal imprisonment in a lamp, basically stripping him of the benefits of all his wishes, means he deserves what he got.
(Note that when Jafar wishes to become a genie, he’s immediately trapped in a lamp, suggesting imprisonment is the “natural” state of geniedom. Thus, the freed Genie at the end of the film represents a perverted abomination of nature. Furthermore, is it reasonable to assume that Genie was also once a man who was somehow turned into a genie, or do genies exist as entities separate from humans? Sadly, the film provides few hints to the answer – unless you assume it’s set in the far distant future, and Genie was somehow trapped in his lamp sometime around the late 20th century and has languished there for millennia. It’d certainly explain all his relatively contemporary pop-culture references, which would be lost on Aladdin.)
So while from Aladdin’s perspective the moral of the story is “wishes can’t grant happiness”, from Jafar’s perspective the moral is “wishes can grant happiness, but only if you choose your wishes carefully, you idiot moron.”