Because actions speak louder than words, peanut. You an Amazon, now dance in celebration.
Maybe you are just subconsciously trying to hide your true submissive nature cause you are a little insecure and need to feel more in control. <br />
Or maybe you are really a dominant personality but don't realise it yet. <br />
For myself, i can be both, depending on the people around me or situation, i switch to suit my environment.
as a defense mechanism. you are feeling shy or dominated so you respond with making yourself puffy and bigger than the person who is running over top of you.
RighteousGirl is right - people 'bow up' when threatened.