If I am joking, I am a "wooden stick". What does a stick mean? What is the representative significance?

Some people say that so-and-so is a "wooden stick", which shows that this person's mind is too simple, or that he is unreasonable at all. When someone says something, he suddenly blurts out the word "wooden stick", which must mean that it is not done well enough or even stupid. In a word, the word "wooden stick" is used in different occasions except as a tool, but its basic meanings are "straight", "too simple" and "don't know anything", which should be the association derived from the shape of wooden stick. In his famous cross talk "Empty City", Mr. Hou used a wooden stick to describe and express a spectator who walked on stage in a daze and followed a walk-on These characters are so vivid that you can't help laughing after listening.