In my psych class, we were discussing whether or not we (the students in my class and I) are adults. The majority of the students said that they were not, while only a few considered themselves in adulthood. Then we went on to debate whether the age group people perceive themselves as being a part of is reflected in their behaviors and the way that they act. For example, if you consider yourself and adult, would you try to be more mature than just shrugging it off and being like "eh, I'm still a teenager..." Acting in such a way might be stereotypical, but nonetheless it is the way that society defines these ages. I suppose that is the reason that we tend to over exaggerate certain behaviors when we are acting like a certain age group, whether or not we really would behave that way in real life.