Grunt on the Ark:''If I chase him, then I catch him, and then I don't know what to do!"
One of my favourites, a grunt again:" You know at this point, if the demon gets us... and rips out our little skulls, and takes off our backpacks, then humps us with his big, demony, butt... we deserve it! haha!
Or swapping weapons with an elite on the covenant:"One word for you: kfyebtazmeplh!"