Bulls in dreams commonly point to stubbornness and a drive that pushes forward regardless of obstacles. A charging bull can reflect anger or determination you've been holding back, while a bull you manage to stand your ground against may suggest you're learning to meet forceful situations without simply reacting. The dream often asks where persistence has quietly tipped into rigidity.
Mars of a nativity, and not joined to good planets, signifieth the native to suffer by envy and hatred. - William Lilly (1602.-1681.)