complexity of meanings

I'm been quite intrigued today, reading the various comments to my One Single Impression poem (see post below), discovering that most people ascribe positive connotations to the phrase "wearing one's heart on one's sleeve." I begin to wonder why was it that the young man who accused me of wearing my heart on my sleeve had imputed a negative connotation (a view that I had adopted over the years) -- where did that come from, was it an idiosyncratic interpretation or was there a broader cultural source?

The denotation or overt meaning of the phrase "wear one's heart on one's sleeve" is to show emotion, affection or love openly for all to see. In itself does appears laudable and positive. But doing a little bit of Googling reveals that one of the first uses of the phrase can be found in Shakespeare's Othello, produced in 1604. In the play, the treacherous Iago's plan was to feign openness and vulnerability in order to appear faithful:

Iago:
"It is sure as you are Roderigo,
Were I the Moor, I would not be Iago:
In following him, I follow but myself;
Heaven is my judge, not I for love and duty,
But seeming so, for my peculiar end:
For when my outward action doth demonstrate
The native act and figure of my heart
In compliment extern, 'tis not long after
But I will wear my heart upon my sleeve
For daws to peck at: I am not what I am."

So Shakespeare presents wearing the heart on the sleeve as a sham, a play act, a deception. The open expression of feeling is mere artifice, a means by which one can manipulate others. Clearly it was Shakespeare's usage that influence the young man who criticized me so long ago, and influenced my own interpretation of this phrase.