All energies no matter how different work on the same principles. They need to be charged or fuelled to give a return. The wind turbine needs wind. The solar panel needs the sun. The battery needs electricity to charge.
Friendship is an energy that works like all others. But it takes two people to charge a friendship when one stops putting into the friendship it no longer exists all you have is one person fuelling the unlit friendship hoping it will light. This energy is wasted and eventually burns out. Then in turn the energies are matched with no input.
So next time you ignore or fade away just remember you’ve removed your energy to something that requires it. The person you ignore will continue for a while but they too will run out of energy so your friendship will be no more.