"Left" vs "leaving" - there seems to be conflicting advice in WWT (AU) and AIP, "leaving" makes much more sense to me as cannot be confused with a direction of turn (ie left or right). Ambiguity is indeed the enemy!
Readbacks - please everyone learn what needs to be readback - it's in the AIP and quite clear. A lot of people read back way too much.
Contacting approach - you can append "visual" if you reckon you can make a visual approach. If you are "in cloud" or "on top", then you do NOT have tell anyone (and everyone) about it. Again quite clearly set out in the AIP.
My other gripe is with people that say "Taxies this time" or "approaches 5000" or "maintains FL140" - please guys, that is not even proper English, let alone to be found anywhere in the AIP or WWT, you are "taxying", "approaching" or "maintaining".
OK - rant over.