The worst example I know is watching The Big Bang Theory on E4 HD (Sky). The sponsorship intro is stupid loud compared to the main programme - which is in 5.1 at a much lower level. So you push the volume up to 70 for the main event and get a heart palp at the advert break.
In the end I gave up, not just because of the quite reasonable grumblings from the other side of the sofa about having to faff around with the volume all the, but my own frustration at the poor implementation - my day job is working in broadcast TV specifications and testing

I now listen to everything from broadcast in stereo as this is reasonably consistent (but not quite). If you're lucky I think a lot of 2.0 audio seems to be pro-logic (analogue surround) encoded so the 568 can extract an interesting rear pair or at least synthesize something.
V. poor.
Ian