All violence would stop.

What if all major terrorist organizations suddently went bankrupt and surrendered?

Nothing because it wouldn't exist in first place. (Lol you hate fate for putting me here at this particular time XD)
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What if I was there instead of Stalin in WW2?

Well that wouldn't muffin because howitzer while until collapsar scheiza.

What if I accidentally set off a revolution?

America or Russia would get invloved and screw everything up.

What if I created my own state that became a global superpower?

You would create your own state that became a global superpower.

What if my face became a giant howitzer?

Then pancake valid.

What if I didn't eat my twarog sandvich when I ate it?

A paradox would be made.

What if the organized mafia suddently had the same power as the US president?

The mafia would have a lot more say than congress. 

What if all the countries united and formed a new government?