Did You Really Work?

I'm watching a video about fluids by Khan Academy. I haven't finished watching. I've just laughed when the narrator says, "Work is force times distance." That is right. I laughed because I remembered what my mother said long time ago.
One day, after getting not-so-good mark, someone said, "But I've worked hard." I actually forget who said it. It was either I or my mom's student. My mother responded by saying, "Work is force times (distance of) displacement. If your force doesn't cause any 'distance' then your work is zero." My mom can be what people call "tiger mom" sometimes.
Let's talk about work in physics term. According to the Physics Classroom, "When a force acts upon an object to cause a displacement of the object, it is said that work was done upon the object." 
In that link to the Physics Classroom, there are some examples of work and not-work. An easy example that is often used is, when I push a wall and the wall doesn't move, it means that the distance of displacement is zero. And, no matter how much force I give, if it's multiplied by 0 then the result is 0. Thus, my work is 0. Another example: I push a car toy and it moves. It means that there is work.
So, next time you work on something, make sure that your force causes "displacement".
Note:
While writing this post, I asked my mother, "Mom, what did you said long time ago? Work is force times displacement?" She said, "Yes. If the object isn't displaced then the work is 0." I asked again, "So if I fail in my test then my work is zero?" My mom responded, "That's right." 
Note again:
In Indonesian language, we use the term "perpindahan" which means displacement when talking about this physics topic. We don't use the term "jarak" which means distance in this case.