Microscopically sharp edges of any sort are the most likely to fracture, fragment, decompose, or oxidize. For one thing they are mechanically weaker than smooth surfaces, and for another, they have a larger surface area in relation to their volume. (only the surface of a solid is exposed to reaction with anything in the solvent or gas that it is immersed in). So if you have scratches in your glass or in your spoon, the edges of those scratches and rough places throughout the scratch will tend to flake or react (if reaction is possible).
Both glass and stainless are nearly chemically inert under most household conditions, however, and glass is so hard that even very sharp edges can remain unchanged for centuries. I wouldn't worry about any leaching or small particles from scratching either stainless or glass, unless you are deliberately trying to abrade the material.