I briefly used Netflix several years ago, and was astonished at how good the recommendations were. However, I aggressively rated many movies in their catalogue

I briefly used Netflix several years ago, and was astonished at how good the recommendations were. However, I aggressively rated many movies in their catalogue to get better recommendations, movies I'd seen before not necessarily just movies I'd watched on Netflix. When I talked to others who had it, and didn't like their recommendations, it seemed to be because they weren't rating the movies at all. Maybe they couldn't be bothered, maybe they assumed it would know based on what they watched, or maybe because these were couples I often talked to it was awkward to bring up rating the movie when there were potentially two different opinions on it, and one or both parties unwilling to debate the issue...