You're right, all forces act in pairs! This is Newton's Third Law of Motion: For every action, there is an equal and opposite reaction. Here's what happens when a force is exerted:

* Force is applied: Let's say you push a box. You are applying a force to the box.

* Equal and opposite force: The box, in turn, exerts an equal and opposite force back on you. This is why you feel resistance when pushing the box.

* Forces act on different objects: The force you apply acts on the box, and the force the box exerts acts on you. The forces act on different objects.

* Resulting motion: The net force determines the motion. If you apply a stronger force than the box's resistance, the box will move. If the forces are equal, the box will remain stationary.

Examples:

* Jumping: When you jump, your feet push down on the ground (action). The ground pushes back up on you with an equal force (reaction), propelling you upwards.

* Rocket launch: A rocket expels hot gas downwards (action). The gas pushes back on the rocket with an equal force (reaction), sending it upwards.

* Swimming: You push water backwards with your arms and legs (action). The water pushes you forward with an equal force (reaction).

Important note: Even though the forces are equal and opposite, they don't always cancel each other out. This is because they act on different objects, causing different effects.