In describing forces, one needs to take note of the “on” and “by”. We need to mention the object the force exerts on and the agent that exerts the force.
For example, the weight of the block is the gravitational force by the Earth on the block.
Note: If you prefer gravitational force on the block by the Earth, that is fine too!
Why is it useful to take note of the “on” and “by”?
Reason 1: Students can check their free-body diagrams easily.
Students should draw the forces acting on the object on the object’s free-body diagram (FBD). Forces exerted by the object on other objects should not appear on the FBD. By labeling forces with the “on” and “by”, it helps students to find out if they have the correct forces.
Reason 2: Students can identify Newton’s 3rd law force pairs easily.
Newton’s 3rd law says that when object A exerts a force on object B, B exerts an equal and opposite force on A. If we take note of the preposition “on”, clearly, the force pairs do not appear on the same object – one is on A, the other is on B.
So, when students see two forces acting on the same object, and they are equal in magnitude and opposite in directions, students should NOT identify this pair of forces as Newton’s 3rd law force pairs.
On another note, students should also recognize that the pair of forces are of the same type. For example, the Earth exerts a gravitational force on an apple, the apple also exerts a gravitational force (equal in magnitude, opposite in direction) on the Earth.
Reason 3: Students can tell the difference between work done on gas and work done by gas (hopefully
The definition of work done by gas is:
The work done on gas is the opposite of work done by gas:
This difference gives rise to different forms of the 1st law of thermodynamics, 
In the first version, W is the work done by gas. In the latter, W is the work done on gas. These two forms can be seen in different textbooks.
These two equations for 1st law of thermodynamics are the same. Maybe the latter version is more intuitive, because it means if you want to increase the internal energy of the gas, you need to supply heat to the system or do work on the system or both.
These are the 3 areas that I can think of, if you know more, let me know!
Chang Physics Class 