Black is intimidating, unfriendly and unapproachable because of the power it exudes. It can prevent two-way communication because of its intimidation.
Black implies self-control and discipline, independence and a strong will, and giving an impression of authority and power.
The color black relates to the hidden, the secretive and the unknown, and as a result it creates an air of mystery. It keeps things bottled up inside, hidden from the world.