I once had a pair of very nasty RCA stereo interconnects - no idea how I acquired them but they looked $2 Shop quality, felt thin and cheap in the hand, and indeed sounded worse than my other pairs. Discovered this when my FM tuner just sounded dreadful - trying to trouble shoot I realised I has installed it using the budget pair. Replacing them with simple DSE-quality cables things improved immeasurably.

Some cables actually aren't up to spec. I now a bunch of $100-odd interconnects I've picked up over the years for $20-$30 apiece.