Answer:
The sense of human smell is so complex that we still do not know how it works in all its breadth, it is postulated that there are two senses of smell and not one: the orthonasal and the retronasal.
The orthonasal would be the external olfactory sense, which takes place when inhaled and that allows us to detect odors from our environment, such as food or that pine-shaped air freshener that hangs inside the taxi.
Retronasal olfaction is an internal sense, which occurs when exhaled, enabling us to perceive the qualities of what we just ingested, just at that point where we can swallow the food or decide what would be better if we spit it out.
The orthosanal olfaction gives us the pleasure of anticipation. The retrosanal, the reward. What happens is that the reward is not always up to anticipation, as when ordering a cake that smells very good but, when you start chewing it, we notice that the taste is not so much.
