Because this energy flows from your customer to other people, when it comes back to you, it comes back to you multiplied.
This is fundamental in business.
As a side note, you should seek to lead your customers with what they want and not what they need, at least, at the onset.
Because people think in terms of energy and whether or not your product is going to help them to get over their problems (low energy state). It may be what they need, but generally speaking, they're not thinking in those terms.
They are generally in the give-me- what-I-want frame of mind, so you have to meet them there. So, when you house your energy in your product, and your customers come to you, they say, “I want that energy that you have invested so that I can use that same energy to go to my next place.”
Do you see that?
The law of supply and demand is a law of giving and receiving energy and wanting to give and wanting to receive energy.
Wanting to give comes from you, the supplier.
Wanting to receive comes from your customer.
You have to understand that the more energy that you invest in your product, in making it better, in making sure that it touches all the pain points of your customers and so forth, the more energy you can ask for and get back in return.