From Season 1's "Hearts And Minds".
Sayid - Let me ask you something -- which way do you think North is?
Jack - Sorry?
Sayid - North? Which way is it?
Jack - Uh, okay.
[Jack looks around and points.]
Jack - The sun's going to set over there, so that makes that West.
[Pointing in another direction.]
Jack -That'd be North. Yeah.
Sayid - Correct. That's where North should be.
[Sayid shows the compass to Jack. North isn't showing correctly on the compass.]
Sayid - Yet that is North.
Jack - I'm not. . .
Sayid - A minor magnetic anomaly might explain a variance of 2 or 3 degrees, but not this.
Jack - What are you saying?
Sayid - I'm saying this compass is obviously defective.
Knowing what we know now, I think Sayid was a little off the mark there.