>>54135808For the majority of human history, lightning, thunder and anything related to the skies has been held in extremely high and mysterious regards. There's a reason why lightning/sky deities are often either their pantheon's top deity or at the very least among the strongest. They also didn't have the same perception or understanding of thin air that we do today, it was usually wind/storm grouped together. These traditional elemental systems are attempts to rationalize interactions between types of matter and tie them to philosophical concepts of the souo and nature, more so than the rpg-fed concept of elemental systems that we have today.
Within the context of the chinese elements, you could try to understand lightning as the link between wood and fire (lightning strikes the forest, produces wildfires).