What does the quote The greatest griefs are those you cause ourselves meaning?

There are many "griefs" that completely outside of our sphere of influence - like a giant hurricane or getting fired because of a restructuring of your company. But those are impersonal forces. The griefs that are our own fault - something said in a weak moment that causes you to lose a friend ... etc. are often much worse mentally because we know that they are entirely the result of our failure ... there is nobody to blame.