In many game situations it can pay to be crazy prepared. You need an answer for everything the GM throws at you, and the less you have to think on your feet, the better.

The character you want to emulate here is Batman. He carries around a piece of kryptonite, just in case Superman turns evil.

You should carry around a piece of kryptonite too. Just in case an evil Superman shows up in your elven forest.

Transcript

GM: Luke, you arrive at the coordinates.
Luke: Han, you there? Princess?
GM: The Falcon is nowhere to be seen.
R2-D2: I hate to point this out, but we're not actually at any of the rendezvous coordinates. Maybe next time you'll leave the navigation to an expert, i.e. me.
Luke: We're at the double secret rendezvous point. Only myself and Princess know about it.
R2-D2: If I was a weak organic being I'd feel hurt at your lack of trust.
Chewbacca: Meanwhile, back near Hoth: 3PO, are you glad you don't need to translate R2's beeps, now that he's out of the system with Luke?
{beat}
R2-D2: Okay. This tone...
[SFX]: < boop >
R2-D2: is me saying "no", this one...
[SFX]: < whirr >
R2-D2: is "yes". This...
[SFX]: < bee-oop >
GM: How are you telling Luke that boop means no and whirr means yes?