If there's one thing you can guarantee in a game, it's that as soon as you declare that you've won, you'll lose.

Being a good and realistic GM, you should ensure that this happens to the PCs a lot.

Transcript

Yoda: I throw the Senate box back at Palpatine! One point to me. That means I win!
[SFX]: Whooosh...
GM: Palpatine leaps aside just in time.
[SFX]: leap
Palpatine: I don't see why I should play by the rules of a traitor.
[SFX]: wmmm...
Palpatine: My job is to look after the people of the Republic.
Yoda: That doesn't make you a good man.
[SFX]: Kzzrkzzzkk!
GM: He zaps your sword. Dex roll.
Yoda: 1. Uh oh.
GM: You drop it.
Palpatine: I'll look after them long after your Rebellion is dead.
Yoda: People need their freedom to prosper. Mackavelli says so! See?!
R2-D2: That's in The Prince?
[SFX]: Kzzrkzzzrkzzzkk!!! {Palpatine tries Force Drain on Yoda; Yoda resists it}
Yoda: It's on the blurb. It looks like a nice book.
R2-D2: Wow... Worst. Blurb. Ever.
Yoda: Besides, mollycoddling never leads to any good. Just look at Ben!
Obi-Wan: Can the mockery wait until after our respective battles to the death?