I burn the breast of the one who has me; yet he or she, if foolish, will carry me on and on within them. The thorn of the rose and not the petal, the sting of the bee and not the honey, the burning of the sun but not its light all are shadows of this pain. I have caused the occasion of self-harm to the weak who suffer from me. I am a one-way street that would be a two-way one if I were healthy. I may delude the one who has me into violence or despair. My object does not want me. What am I?