A cusp node makes a sharp corner. The
Asymmetric and
Symmetricnodes are called
Smooth curves. In the case of the
Asymmetric node, the control handles can be lengthened or shortened independent of each other, but if you try to change the direction of one, the other follows, keeping both handles in a straight line. Change your node to an
Asymmetricone and see what I mean. It's not possible to make the same pointy shape you could with the
Cusp node.
With a Symmetric node, the curve handles behave similar to Newton's Third Law of Motion: "For every action, there is an equal and opposite reaction". Neither curve handle can be moved without the other moving in an equal and opposite direction, maintaining handles of equal length and opposite direction. Change your node to Symmetric to get a feel for what you can do with a Symmetric node.