It is fun to smell

There are all sorts of jokes about smelling, because sometimes that word is a verb (which shows action), and sometimes it is an adjective (which describes a person, place, or thing). When we say, "Something smells," we usually mean that something has an unpleasant odor. When we say that it is fun to smell, we mean that testing things by their odors is fun. Sometimes it isn't fun!

People who actually use their senses of smell to test things usually say that they "sniff" whatever substance they are testing.

Our sense of smell is not as acurate as that of some animals.
An animal's sense of smell is a tool for survival; for finding food, for finding others of its kind, for recognizing its family, for detecting enemies coming close to them. Our sense of smell can be a tool for survival also, in that we can recognize the smell of something burning or the smell of a gas leak (if we are awake), the smell of spoiled food, of chemicals having toxic fumes, and a few other scents that tell us there is a danger. However, we have had to learn to know these scents. We can smell brownies baking in the oven, but our lives do not depend on our ability to smell food. We have other ways of finding food. Just as we have learned the scent of roasting meat, we have learned how to go to the refrigerator!

Our sense of smell is considered by some to be "mysterious." Certain scents can bring memories of events to our minds. Some scents make a picture come into our minds. Some odors make us feel relaxed; others make us feel peppy.
Most people enjoy the scent of fruits, flowers, and spices (to name a few); most people find the odor of garbage and barnyards unpleasant.

Our sense of smell is connected to our other senses in a way that is unique to humans; the more we know about the world, and the more we experience, the more highly developed our sense of smell becomes.

Have you noticed it is easier to detect odors when we close our eyes, and when it is quiet? When we sniff something to find out what its scent is, we usually describe it as smelling like something we know about. We may say that something smells "minty," or that it smells "chemical", etc.
Just as there are four basic tastes (sweet, sour, bitter, and salt), there are seven basic smells: minty, floral, ethereal, musky, resinous, foul, and acrid.

People have used incenses and perfumes since almost forever, because pleasant aromas make us feel good. We know that perfume smells different on different people, because our individual scents blend with the perfume.