Are you sure you see the reality out there? That is the question. The brain does not receive an image like a camera does. The brain is not a passive processor. What you see is constructed in the brain. How do you see with your brain?
Our olfactory organ is quite exceptional. What you are capable of smelling can change within a few months as a result of changes within your nose. And a smell apparent to one person may be completely undetectable to another.