Ever noticed that your perfume disappears after a few minutes? The truth is that it’s still there, but your nose and brain stop noticing it because it becomes familiar. Once your brain realises that it’s not harmful, it just ignores it. In fact, if you have a signature scent that you use all the time, your brain becomes so used to it that it barely notices it at all, and you’ll only be able to smell the top notes of the scent every time you spray it.