April, I can assure you that I don't make excuses. I've studied people for years. Certain mannerisms at given events,etc and everyone acts differently dependent on what " class " of people they are.Yes,classes,because there is a marked difference when it comes to how each individual behaves/reacts in the circumstances in which they find themselves in.
Yes, I know about behavioural psychology, Lookout

The interesting thing about it is, that whilst people may tell us that they are acting in a certain way, the onlooker, by means of those mannerisms you mention, often experience something quite different. The behaviours learned by different levels of people is generally believed to reflect on how they cope with life circumstances.