Sometimes you wonder why Ranma and Genma didn't dump themselves in the right spring as soon as Ranma had cooled off for getting cursed... Then you realize why: while Ranma was cooling off, Genma and the guide tried to boil a piglet that was actually Ryoga. Considering his super-strength and that he had good reasons to kill the two idiots, can you blame them for running away, taking Ranma with them?
- Then why has no one ever cured their curses as soon as they got them, and why does nobody ever cure them in the series? Despite the fact a lot of people ask this, it's quite simple, really (even ignoring the whole "Status Quo Is God" thing that Rumiko had serious problems with adhering to). Ignoring the obvious reason why in the penultimate storyline, where Jusenkyo is flooded and, for whatever reasons, they decide they all have to go home to Japan as soon as possible instead of waiting for the floodwaters to recede and restore the magic in the springs, we have the following:
Ranma: Firstly, he gets dragged along by Genma from the angry Ryoga. Then, shortly afterwards, he gets chased out of China by Shampoo. Once in Nerima, Genma refuses to let him go from Nerima while he's not married to Akane, as he doesn't trust Ranma to come back to his fiancée and/or he's determined to get the two kids wed as quickly as possibly. Furthermore, Ranma has no money to afford a quick trip to Jusenkyo anyway, meaning he'd have to swim or stowaway to reach China in the first place and then walk & hitchhike his way to Jusenkyo and back.
Genma: He caused Ryoga to attack in the first lace, and then had to flee China with Ranma. Once in Nerima, he stubbornly refuses to go back to China if Ranma will not marry Akane first. Besides, he's a lazy bum and doesn't mind his curse so much as Ranma does, so he can happily live with it until he can successfully mooch off of Ranma's attempts to get cured.
Ryoga: Chases after Genma (and, unknowingly, Ranma) as a result of being near-cooked and promptly gets lost
. Logically not knowing that Nanniichuan can cure him at first, he bumbles around and eventually goes back to Japan looking for revenge on Ranma
. Once in Japan, he can't find his way back to China because he can't find his own backside with both hands and a road map.
Shampoo: Got given her curse as punishment for coming home in defeat; ergo, she cannot cure it until she erases her shame by winning Ranma's hand.
Mousse: Honor Before Reason
as to why he initially keeps it; he was foolish enough to be cursed, which is clearly a mark of shame to the Joketsuzoku, so he decides to keep it until he proves himself by winning Shampoo's hand. Plus, he's too paranoid about the idea that Shampoo and Ranma might get married if he flies away to Jusenkyo while they're alone in Nerima.
Taro: Actually likes his curse, because it gives him a One-Winged Angel
powerup that lets him bully and bash his way through life. He doesn't want
to be cured, which is to be expected since he's had it his entire life.
Rouge: Again, her Jusenkyo curse is a One-Winged Angel
; it gives her the power to defend herself and destroy her enemies without posing any impact to her life. It's Cursed with Awesome
at worst, and just plain awesome at best. She doesn't want to be cured.
Herb: Gets Mode Locked
moments after getting cursed, meaning he can't cure himself. The whole point of his story arc, for him, is finding a way to get unlocked so he can then go back to Jusenkyo and cure himself.
Kiima: Deliberately cursed herself for tactical advantages and has no time to cure herself on-screen before things go ka-blooie.