Wisdom is not learned through a textbook. It is learned through experience, trials and tribulations, joys and sorrows, successes and failures. Most of one's wisdom comes from going through a situation, learning the particulars, positive or negative, and carrying that knowledge to another situation that may be similar, so one does not make the same mistake or so one can revisit the joy.
Wisdom is gained when one becomes introspective, analytical, and evaluative. Every relationship teaches a lesson. It is important that we think (there is the key word), "what did I learn about myself from this relationship?" Every occasion, good or bad, teaches us about ourselves. Every situation, positive or negative, teaches us what to avoid and what to welcome.
Yet, there are times when each of us fail to learn the value of the lesson. We carry on without learning anything at all, and then repeat faulty behavior, never gaining wisdom from the experience.
Socrates was the wisest man, for he knew that one does not stop learning till one stops breathing. No one can know everything about everything. We can only hope to gain knowledge and wisdom everyday as we live each day. I have a wonderful sign in my classroom. It states, "What new information did you learn today?" I think that says it all.