The 'My car-only-does-one-speed-and-I'm-sticking-to-it' syndrome

I do enjoy driving. And at the time of morning I leave for work the Chilterns look at their best...beautiful sunrises, changing seasons...the usual. I particularly like the clear highways which, apart from the liberal and nightly topped-up sprinkling of road kill, usually make the whole experience very pleasant....except when you are going along at 60 mph along the road from Little Chalfont to Chorleywood and someone in an MG ZR pulls out in front of you so that you have to slow right down....nothing behind me so they could have waited for me to pass their junction. I could forgive them..... but they then proceed to do a steady 40 mph which, when we get to the 30mph zone, they continue to do. Just irritates me. That's all. Sorry. Got that out of my system.