"...he bought a guitar from me and never paid me in full."

My effort to depend on goodwill to provide my economic sustenance has required me to sort those I can do business with from those I cannot, and I have learned that I must respect the signals I am given by folks I seek to include in my economic network. The signal that folks will not fulfill their obligations reveals that I can not include them in my network in order to avoid economic harm that results from including those people. Some people can't afford goodwill, and failing to meet obligations demonstrates they cannot afford goodwill.

Excluding them from my economic network avoids losses that reduce my wealth, which optimizes my economic prosperity, as well as my social interactions, which is good.

Thanks!