When is the work done by a force positive and when is it negative?

(N/A) The general formula for work done is $W = \vec{F} \cdot \vec{d} = F d \cos \theta$,where $\theta$ is the angle between the force vector $\vec{F}$ and the displacement vector $\vec{d}$.
$1$. Positive Work: If the angle $\theta$ between the force and displacement is in the range $0^{\circ} \le \theta < 90^{\circ}$,then $\cos \theta$ is positive. Consequently,the work done $W$ is positive. In this case,the force aids the motion of the body.
$2$. Negative Work: If the angle $\theta$ between the force and displacement is in the range $90^{\circ} < \theta \le 180^{\circ}$,then $\cos \theta$ is negative. Consequently,the work done $W$ is negative. In this case,the force opposes the motion of the body.