It can indicate heart problems - especially if it get close to a blue or purplish color. This often fluctuates through out the day, in the beginning.
A pale comb, almost a whitish grey with a bit of pink is usually the color of molting.
Swollen red, is a sign pullets are getting near laying - about 3 weeks. Or hens returning to lay in the spring, coming out of molt.
A bright red comb is attractive to a rooster. It often indicates that mating would be allowed. Some very good roosters won't bother pullets until this gets that bright red, whereas juvenile roosters, often will mate despite not being red and receptive.
I too, do not think of it as an emotion, but rather a hormonal level indicator.
Mrs K