Inkscape - Pencil Tool (F6)

About

The pencil tool is the easiest way to draw a path

Steps:

Click on the pencil icon (F6 or p) in the Tool Box
Click-drag the pointer over the canvas to draw a line. While drawing, holding down:
- the Shift key:
  - temporary disables nodes snapping to the Grid or Guide Lines.
  - add the new sub-path to a selected path
- the Alt key enables the Sketch mode. All strokes are averaged to create a final stroke, temporarily shown as a red path. Releasing the Alt key finalizes the path. Draw all your strokes in the same direction.
Shift + Enter to close the path
Simplify the Path. Path → Simplify (Ctrl+L) command one or more times.

Mode: Bezier, Spiro, BSpline
Shape: None.
The Smoothing value have an impact on the number of node. Range from 1 (minimum) to 100 (maximum). 30 give you a reasonable number of nodes.