As a human, you are more able to handle hallucinations than you think. If you see a bear off in the distance, in real life do you freak out and drive off the road? No. You just remark at it. "Holy shit a bear in the distance!"

When you're on acid, you don't change as a person, your reactions don't change. If you see something weird you say "woah, that's weird" but, unless you're deep in a trip and forget you are on a substance, you can usually handle it like a normal person.