Meant to include an example of chord ambiguity in my last post. One of the most complex tunes I've ever attempted, in terms of potential chord structures, is Jerome Kern's All The Things You Are. (The link is to a short improvisation around the tune). Many of the chords are improvised around the melody, and the melody line itself is embellished - all on the spur of the moment in a one-take effort.

Whether any of it is "correct" or not is a matter of taste...