We normally think of tension as a bad thing.
It certainly can be in the material science world, especially when the tension exceeds the breaking point of a material.
It also can be problematic in the biological domain—after all, no one wants to have hyperTENSION.
But in the writing world—in fiction, non-fiction, and even poetry—tension is a brilliant tool to maintain reader interest, and the effective pacing of the resolution of that tension can make or break a piece of writing.