Aries is Moving\Active Fire - The element of Aries is Fire and nature is active or movable. It is fire which spreads and spreads quickly.
A very active person which loves to do new things, start a new venture, go on a new adventure and loves the feeling of excitement which accompanies new events. It has a lot of energy to do new things but not necessarily the patience to complete what it started. Strong Aries dominated can leave a task in between and start on a newer one (unless other balancing factors are present).
First sign of Zodiac - This is First sign of Zodiac which also shows its initiation and beginning tendencies. Especially in young kids if Aries is not controlled they can leave a lot broken things in home.
Aries represents the Head and Brain of Human beings. We know that basic nature of Fire is to transform things from one form to another (e.g. from raw food to cooked food, from wood to smoke etc.)
And brain is one part of human which is constantly doing Transformation -
Signals from various sense organs, nerves spread all across body, the visual signals, the voice signals, the smell , the touch sensation, the wound in body, the tickle in legs and millions of such nerve signals are constantly fed in to brain it transforms those in to workable information.
Thus, Human Brain is by far the most Active Part of body which constantly (24x7) works without ever going fully off duty. Aries domination (and in general Fire signs) provides a lot of activity and also reduces the sleep requirement for a person. Among all people Fire signs need least sleep and among fire signs too the Aries requires the least amount. In a negative way, Aries are most prone to Insomnia and may keep up all night long.
Apart from synthesis of signals, Brain actually controls various functions of the body and this shows the bossy characteristic of Aries natives.
Thus Aries is the most ambitious, decisive and explosive warrior sign which symbolize the big bang and creation of world.