¡bah!

¡bah! - an interjection which you use when you are surprised about something and disagree, or had previously believed otherwise, like "huh."

Diego: Me encontré con Marcelino en el Proa ayer.
Marcelo: ¡Bah! Pensé que estaba en Australia.

Diego: I ran into Marcelino in el Proa (the bow) yesterday.
Pato: Huh. I thought he was in Australia.

¡miiiiish! - an interjection to use when you are pleasantly surprised

Walking through town you run into a friend:
¡Miiiish! Que bueno encontrarme contigo!
¡Miiiish! How nice to run into you!

Chilenismos? I found bah here so perhaps it's more widely used than in Chile. Coloquiales