Why Would I Lie?

It was obvious that being split up into different wormholes shook them up, but the stories that they were able to tell after were priceless. Lance hung to every word that came from their mouths; so why do they think that everything that he told them was a lie?

(Allura, Keith, and Pidge think that Lance is lying about saving a planet, they don't think that it would ever be possible for him.)