The example that shows unbalanced forces acting on an object is:
"Two people are on the same side of a large box. One person pushes the box and the other pulls the box with equal force."
In this scenario, the forces are acting in opposite directions (one pushing and one pulling), but since they are not equal (they are acting in different directions), they create unbalanced forces on the box, which will likely result in the box moving in the direction of the stronger force or have a net force that is not zero.