Controlled Fusion would give us power over matter itself. Extended to the far end, we could create every element on the periodic table simply by using fusion generators to slam bigger and bigger atoms together. We'd never want for anything as a species or a culture ever again. The entire economic structure of the world would break down, since nothing material would have inherent value anymore. Ideas would be the only thing worth exchanging, but they'd no longer be worth fighting over because control of natural resources would be of no value for the groups that espouse conflicting philosophies.

I hope this happens in my lifetime.

Would you really change how you live, because i don't think i would.

that wasn't really the question. The question was what would deal a great blow to how you percieve the world. A world where the future can be told by the positions of the stars millions of miles away is a world radially different to how I believe the world actually is.
Proof of such things would indeed force me to rexamine my understanding of the world.

Discovery of other human-like life forms would definitely shake my world view. Also a definitive answer on the origins of man. Very intriguing.

Finding that George W. Bush was right would probably shake my world view to the point of insanity. Fortunately, the odds of that are similar to him winning the nobel in literature, so I am not worried.

I hate to burst your bubble but people will always have something to fight over since ideas will usually clash, and land will become more precious. Unless you hand everyone their own universe, wars will always exist in one form or another.

What would shake my world view? If I could see myself the way others see me.

Falling in love, maybe?

If the suffering stopped and didn't come back. No more samsara.

Hell, if the guy can win presidency without being elected, who knows?

Meeting myself, either from time-travel, or from cloning, just seeing a seperate entity that somehow shared my identity would really freak me out.

or

the ghosts of all the aborted fetuses throughout history rising up and taking arms against humankind.

or

finding out that some long-dead polytheistic cult was the only "correct" religion.

or

Waking up as somebody else.

or

Apes with weapons.