A spark is what happens when current tries to leap across a gap. Sometimes, the damn thing just won’t work; the gap is too wide. If both sides touch, you don’t really see much, either. Juice flows, but it’s nothing that exciting.
When there’s some distance, some separation, however, and if it’s just enough, you’ll get something wonderful and dangerous.
I mention this, of course, because the time has come to change the adage, “Absence makes the heart grow fonder” to “Distance makes the heart spark more.” Just an idea.