Oh yes - I think Zeds look more expensive than they actually are and this builds some resentment from a few drivers. I come across other drivers that want to show what their car can do or are less than courteous but I also think that part of the problem is folk don't know the capabilities of the Zed and get annoyed when I am looking for an overtake. Another thing that might be an issue is that the Zed can look like any other BMW when seen in the rear view mirror and so folk think you're just being pushy.I've also taken to driving with my lights on as a low grey Zed can be missed easily by some drivers.
Basically though, I think some drivers don't like to see a grey haired guy (or anyone come to that) in a capable sports car with the roof down enjoying themselves. Probably envious and in some cases they feel it threatening, want to compete and prove something. I leave them to it, either well behind or watch as they blatantly break speed limits ahead on straight roads.
I have had excellent impromptu runs with other drivers though ( particularly over Hartside) with folk I've come across that have enjoyed the spirited run brought about by such a meeting - even in one case a driver who courteously waved me on to lead and I did the same at points on the run for him - a big thumbs up when we went our separate ways at Penrith. We also had a great impromptu run with three Lotus 7s on the Hawick route. Wonderful memories.