This is the laplacian operator (in 1D, just the second derivative, or curvature). The sharper the crest, the more negative; the sharper the trough, the more pos

This is the laplacian operator (in 1D, just the second derivative, or curvature). The sharper the crest, the more negative; the sharper the trough, the more positive. If you change the value there, by that much, the effect is averaging (and the discretized form is literally averaging). You've been doing calculus the whole time. There's a difference between knowing the path, and walking the path. Here's a 3Blue1Brown video with intuitive graphics on it https://youtube.com/watch?v=ToIXSwZ1pJU https://youtube.com/watch?v=ToIXSwZ1pJU