Hand planing a piece of clear, straight grained Pine is a wonderful experience. I set it up for non woodworking visitors and it's always a hit. But throw in a knot and the world changes. Fine edges on hand tools and powered can be damaged as can the workpiece. And bits of wood can fly. Sometimes the adjacent wood grain is also troublesome. This is where experience matters so much. The right tool, technique and sharpness can all be challenged.