Here is a neat little saying that sums up a general observation: “Sobre gustos no hay nada escrito” – there’s nothing written about tastes. It’s strange how the literal translation doesn’t sound quite right. Here’s a less literal one: “There’s nothing laid down, or there’s no law about tastes”.
It’s exactly what you say after you’ve been introduced to someone’s horrendous new boy/girlfriend, or been asked to admire some appalling item of clothing. Always best to say it out of earshot though!