The ability and willingness to change one's mind

Probably the attachment that creates the most suffering - both to ourselves and others around us - is the attachment to being right, to believing in our own certainty. As you can see below, the true foolishness of this attachment was recognized many centuries ago by a powerful Egyptian pharaoh:

True wisdom is less presuming than folly. The wise man doubts often, and changes his mind; the fool is obstinate, and doubts not; he knows all things but his own ignorance.

-- Akhenaton