The reviewer who commented about the digital artifacts has a point, but the problem is very easily put right. For some reason, the DVDs in my set often have a small splash or squirt of a very light oil, something resembling clock oil, towards the outer edge. Presumably this arises somehow from the manufacturing or copying process. This splash of oil, if present, should be wiped off carefully with a lint-free cloth. Otherwise there will indeed be annoying artifacts and the DVDs may freeze in mid-episode. But if you clean the oil off the problems disappear. You may need to examine the disc carefully in light reflected from a lamp, to find the splash on a disc. The splash may be tiny, but it will still stop the DVD. Some discs may not have this problem.
The writer of this series is a genius. I would recommend the Creek series to any student doing a university course on scientific method. Creek's comments on the need to get rid of prior assumptions and keep an open mind are the very essence of the best of the scientific approach. The whole series is brilliant.