Antonymous Hemiotics

Curious, no?  I love how this easily shows linguistic contrast, a conflict between semantics and semiotics. 

Words which would naturally fall under the heading of negative evaluative stance suddenly see their semantic prosody shift!

"Wicked" is another example. "Sick", "bad", "phat" (this one at least saw an accompanying formal modification too).  I'm wondering now about the possible reasons behind this linguistic epiphenomenon.

Could hyperbole be at the center?  We're so used to saying something is great instead of good, excellent instead of acceptable, brilliant instead of OK, etc, that when we need a strong word with positive evaluative stance we find ourselves at a loss.  It seems we then look for words which have heretofore been used negatively and subvert their agreed upon semantic value without even having to explain the movement, no need to allude to the metalinguistic reasons! It seems to be universally understood in an instant, and perhaps even the possible reason(s?) is (are?) (an) Unknown Known(s) in our minds.

I'd like to compile a list of such examples, and investigate the factors which cause these shifts.  But I'm awful at writing lists.  Or am I awesome at it?