Om Swami
Why does it hurt so much when someone criticises me, and what is the attachment behind it?
Attachment to your own image
The strongest attachment is to yourself: your ego, your learning and the image you hold of who you are. Whoever disturbs that image causes you pain, because you are looking at your own image.
The greatest attachment a person has is to themselves. Every person is most attached to their own ego, their own learnedness, or their own image.