"The Last Night of a Jockey" is an old Twilight Zone episode about a jockey who gets suspended from riding horses, then wishes he was bigger. The wish, obviously, backfires, because The Twilight Zone was basically one giant PSA about the dangers of evil genies.
Agatha Heterodyne: I'm going to have to think twice about everything I say to you, aren't I?
Castle Heterodyne: It'll be fun!
"I am the genie of the lamp. I provide you three wishes, all of which contain horrible, ironic consequences! Muwahaha!"
LutherBifteck: I bet if I wished I was a shapeshifter
LutherBifteck: The genie would give me the power to change triangles into squares
LutherBifteck: And I would be annoyed.
"Despair for the conceited...that is what you wished for."
— Truth as he punishes Father, Fullmetal Alchemist
Truth: I'm the Truth of your despair, the inescapable price of your boastfulness.
Father: (flashback) Humans who would dare to play God must pay a steep price for their arrogance. That is Truth.
Truth: And now I will bestow upon you the despair you deserve.
— The punishment of Father, Fullmetal Alchemist
Never trust a Djinni. Either through mischief, malice or misunderstanding they almost always grant a wish using it's most literal interpretation.
Doctor Spooky, Magellan
Amadeus Cho: Okay, then. Wishes 101. Whatever you ask for comes back to you in the most jacked up way imaginable. You ask for your dead son back? He shows up as a walking corpse.
A-Bomb: And eats your brain.
Amadeus: There ya go. It's the God's way of punishing us for trying to get something for nothing.
Monica Rappaccini: Does he always talks this much?
Bruce Banner: Yeah.
Amadeus: Right! So you'd say "I wish he'd shut up." and then you end up deaf.
She-Hulk: So you'd say "I wish that, without causing negative repercusions on the health and well-being of any person, Amadeus Cho would stop talking for the next ten minutes.".
Amadeus: Huh. Okay, yeah, that's pretty good!
Prismo:You just gotta be really specific. Say your wish is, "I wish for a backrub". Who's gonna give it to you? A dirty man? A bear? And, where does this masseuse come from? Do I zap some guy away from his family dinner? Leave some kid traumatized? "Mom, where did Dad go?" "I don't know son, he just disappeared from the table, sorry."
—Adventure Time, "Jake the Dog"
Agent Mulder is typing his wish at the computer:
Whereas, I have one wish left and desire to use it most effectively for the good of all mankind, and whereas this wish contains great potential for the betterment of life as we know it, and that equal potential for grave danger, chaos, and mayhem, let effect, a world run amok, and whereas, I must cover all bases…
Jenn the Genie: [reading] "Whereas, I have one wish left and desire to use it most effectively for the good of all mankind..." Yadda, yadda, yadda. "Here on this plane of existence..." Hmm. Hmm-hmm. What, are you a lawyer?
Mulder: Well, I have to be with you. I'm going to get this last wish perfect. I'm not going to leave you any loopholes. I'm not going to let you interpret this as an edict to bring back the Third Reich or to make everyone's eyes grow on stalks.