We've all heard the phrase "Beauty is in the eyes of the beholder". During the Renaissance period, women were considered beautiful and sexy if they were somewhat plump. In the 'Twiggy' era, extreme thinness was considered a sign of beauty. And today, we're mostly somewhere in the middle. If you saw a Botticelli model walk by today, you'd likely think that she'd look much better if she lost some weight.
Whenever I hear the phrase 'Beauty is in the eyes of the beholder", I think of "Consider the source." When you really look at it, both phrases are saying the same thing, it's just that the one focuses on beauty, and the other deals with - well, everything else. Just as you have to know the eye of the beholder, to know whether you're likely to agree with them, you can't blindly accept an opinion, without knowing who is rendering that opinion.
Let me show you what I mean.
I was recently at a barbecue, and someone offered me some of their cake. "It's wonderful!" they said... "best cake ever". I took a bite and had to work hard to not spit it out. On the one hand, there was nothing wrong with the cake. It was moist, and it was thoroughly cooked but not overcooked. The problem was that the cake had a lot of coffee flavoring, and I don't like coffee. The lesson, of course, was that I should have determined if the person rendering an opinion on the cake, shared my food likes and dislikes.. or at a minimum I should have been a bit more cautious before taking a big bite.
And of course this applies to far more than just beauty and food. It applies to everything.
When someone asks me to recommend a book, I first ask them what sort of books they like. As much as I enjoyed Lev Grossman's The Magician King, it doesn't make sense for me to recommend that to someone who mostly reads biographies. And frankly, before they asked me for a recommendation, they should have asked me what I liked to read. I've been doing some writing, and I'm looking for beta readers. But for me to offer my writing to someone who doesn't read fiction, or only reads romance novels, would be a double waste of time. My writing is fiction, and it is most certainly not romance. It would be wasting their time to read it, because they wouldn't enjoy it. And looking at their feedback would be a waste of my time, because their feedback would have no real value. But there's a detail here that shouldn't be overlooked. If you want a book recommendation from me, you shouldn't care what I write, you should only care what I read.
You don't have to be a beauty queen to judge a beauty contest (I got that saying from my mother!), but I want to know what you consider to be beautiful. You don't have to be a good cook, but I want to know what you like to eat, before I take your recommendation. You don't have to make a good cup of tea... but that's because I'll make my own, thank you very much. Some things you just have to do yourself.