Mars is the ruling planet of Aries, and when direct in it's home sign, things flow accordingly. When retrograde however, it can mean upsets in the Mars and Aries archetypes- specifically with aggression, sexuality, impulsiveness, and impatience. These are all the "negative" attributes to the Aries archetype, which can also be heightened during Mars retrograde. Take a look at your chart and see what house Mars lands in- you might find trouble in these areas too!