<span>Proper adjectives have their initial letter capitalised,
for example American - derived from a proper noun America - or Victorian - derived from (queen) Victoria.
Common adjectives, on the contrary, don't have </span><span>their initial letter capitalised</span>, for example green, empty, colourful. Just remember that "common adjective" is not a scientific term used by linguists, it is informal.
Because children and dogs are still filled with a natural hope and expectation that their smile will be returned. They tend to make direct eye contact with you, looking right into you, just grinning away (unless, of course, they have been abused).”
