Know what's funny? If there are alternate timelines, then Lost's rules of Time Travel
... are exactly the same as Dragonball Z's.
(1:20 - 4:50)
Listen to Trunks explanation of why going to the past and making a big change creates an alternate world. The future the world is destroyed by androids because Goku died, so he comes back in time to make sure he lives. What happens in the story is that Goku lives, but that just creates a reality where Goku is alive. The reality where Goku died and the androids destroy the world STILL EXISTS. Even worse, is that the ONE SINGLE action of Goku living wasn't enough to abate trouble completely.
At the time, Trunks believed that one reality couldn't affect the other, but by the end of the Cell saga what he got was INFORMATION that allowed him to be stronger. So when he goes back to his original reality, Goku was still dead and the androids still destroyed the world, but he was now powerful enough to get destroy them after the point when he first left.
This I believe is the same approach Lost is trying. People wondering what's the point of alternate reality if nothing changes fundamentally, well, the one thing that IS changed is the fact that anyone travelling between realities now has information they didn't have before they left, and can now go to the "present" and tackle the problem with knowledge on their side.
Then this will be season 6:
(ep1)KAAAAAAAAAAAAAAAAAAAAAAAAA-MEEEEEEEEEE(ep2)EEEEEEEEEEEEEEEEEE-(ep3)AAAAAAAA(ep4)AAAAAAAAA(ep5)MEEEEE(ep6)EEEEE(e 7)E(ep8)-AAAAAA(ep9)A(ep10)AAAAAAAA(ep11)AAAAAAAAAAAAA - Catch - "Damn it"
Jack = Goku (Hero of the show)
Locke = Master Roshi (Taught Jack how to have faith, plus he's bald )
Sawyer = Vegeta (Bad turned good, plus he and Jack are about equal in a fight)
Ben = Piccolo (Because you never really know which side he's on or what he's up to)
Kate = Bulma or Chi-Chi (Can't decide..)
Hurley = Fat Buu, Good Version (Childlike, lovable, but gets the job done when needed...plus he loves to eat!!)
Desmond = Future Trunks (Sees future, tries to save Charlie instead of Goku)
Walt = Gohan (Locke/Piccolo as his mentor, and he's naturally powerful)
Arzt = Hercule (Talks a big talk, but can't do shit)
Vincent = Icarus (loved pet)
Frogurt = Oolong (Whiny, obnoxious, and good for nothing)
Mikhail = Super Buu (Just won't friggin die!)
Jacob = Eternal Dragon (Powerful, makes miracles happen)
MIB = Omega Shenron (Hate to bring in GT, but he's the evil incarnation/offspring of Jacob)
Widmore = Dr. Gero (Sends bad guys, doesn't do much himself)
Keamy = Broly (No remorse)
Christian = Grandpa Gohan (Taught Goku/Jack everything he knows)
That's all I could think of on the spot hah...yeah I used to watch me some DBZ