Admirable, CT. I can't claim anything as exalted as professional radio training but a geeky youth spent in HF ham radio helped me get the intelligibility quotient up a little bit. At least in the GA environment, I think we're just OK in Australia. The place that impressed me most was South Africa: in the areas I flew, everyone was particularly crisp and professional, and it was clear no nonsense was tolerated.
As LeadSled says though, it's ultimately about getting the message across. We may have a quiet chuckle about some clunky technique or poor diction but, in the end, much better that they have a go and let you know they're out there. I must say that I haven't found the US GA scene very different to Australia. No doubt the locals know they have a foreign devil on their hands but it's all pretty easy to work out.
(Tucson Tower instructing "Y'all mind the F14s mid-field" some years ago gave pause for thought but no drama...although my "traffic sighted" caused them some obvious amusement).
Still, like others here I have a few local pet hates. After several years in WA, I suppose the place that they do the para-jumping is "Brookton". But listening to Centre and the locals, I still can't pick it in the transmissions. For years I was looking from somewhere like "Brooklyn" but, by practicing swallowing a consonant or two, I think I've worked it out.