hmmm, i say gah as a combination expression of surprise and dismay.

when confronted by something, one might use a very very very very very mild profanity. not even using the lord's name in vain, but (and i don't think this violates the rules on etiquette?) 'god'. and it might not even be a profanity, it could as well be a plea.

anyhow, so you start to say that, but then it turns out to be a bit worse than you thought, so then it turns into aaaah! or however you would spell what you scream when running away from a big monster.

for instance, you charge the enemy and some hidden units pop up in front of you. you start to say- 'god, why did you do this to me today?' but then, you notice that there are bazillions of enemy soldiers all over the place, so you change your statement into a scream of terror (i guess i'm suited for the town militia!).