The most horrible example is the Rocky and Bullwinkle Show. Early commercial VHS tapes of it have the original music. Later tapes, and the DVDs, have all the music replaced with just awful generic music. That bad music just makes it unwatchable.

Music is an enormous factor in movies, I wonder why nobody mentions it. For example, the Lord of the Rings soundtrack is spectacular and adds greatly to the pleasure in watching it. In contrast, the soundtrack to The Hobbit sounds completely generic and boring, and the result is unwatchable.

Another example is Star Wars. The first two movies had amazingly good soundtracks. The later sequels had boring music, and whaddya know, the sequels were boring.