What Does the Phrase 'Beauty is in the Eye of the Beholder' Mean?

What Does the Phrase 'Beauty is in the Eye of the Beholder' Mean?
Beauty means different things to different people. Everyone perceives the world around them differently. But what does it mean when someone says beauty is in the eye of the beholder?
Greek mathematicians discovered that beauty is in the eye of the beholder lies in a geometrical formula called the Golden Ratio, which states that a longer triangle should have a ratio of 1.618 to its shorter base. This applies to people's faces and a woman's waist to hip ratio.
Confucius (Chinese teacher, editor, politician, and philosopher) once said, "everything has beauty, but not everyone sees it." This is the closest and simplest way of understanding this idiom.
People are often quick to judge the world around them and label it into what is pretty or ugly. They like what is pretty and tolerate or shun what isn't. However, who defines what is pretty and what is ugly? Everyone individually decides what is acceptable and what isn't. This is where this idiom comes into play. The definition of what is pretty, ugly, or acceptable varies from person to person. What someone might have labeled as ugly or appalling might not be so for someone else.
Meaning
Beauty is in the eye of the beholder literally means that perception of beauty is subjective. Someone or something might not be beautiful for many, but to someone else, it might be ravishing.

The same thing that is beautiful to someone's eyes could be ugly to another. For example, an actor or actress might be handsome or pretty for some, while they might be considered otherwise by someone else.
Origin
The saying was first sighted in the 3rd century BCE in Greece. However, it was altered to the current state only in the 19th century. There were many individual versions of this idiom throughout time.
Benjamin Franklin wrote in Poor Richard's Almanack―"Beauty, like supreme dominion, Is but supported by opinion"―meaning, beauty might be what controls everything, but it too is supported by opinion/perception.
David Hume's Essays, Moral and Political, 1742, mentions, "Beauty exists merely in the mind which contemplates them; and each mind perceives a different beauty.". It couldn't have been said any better. Here, Hume says that beauty exists only in the mind of the person who sees it. So, something can be beautiful for someone because their mind feels it to be beautiful, not for others.
Shakespeare wrote, "Labors Lost Beauty is bought by judgment of the eye, Not utter'd by base sale of chapmen's tongues" in Love's Labor Lost―meaning, only the eyes that see are worth of judging the beauty and not by the world's perception of it.
Actual Coining
Margaret Wolfe Hungerford gets the credit for coining this idiom to its current state. She wrote under the pseudonym of The Dutchess. She first printed the idiom, "Beauty is in the eye of the beholder" in Molly Bawn in the year 1878.
Examples of Usage
"I don't really think Jessica's boyfriend to be handsome, but I suppose that beauty is in the eyes of the beholder."

Explanation: The speaker doesn't consider Jessica's boyfriend to be handsome, but accepts that Jessica finds him to be handsome, and to have chosen to be with him.
"How can you find the movie to be horrible? I thought it was awesome. I guess, that just proves beauty is in the eye of the beholder."

Explanation: The speaker believes to have loved the movie, while his/her companion didn't. Here too it is a matter of liking for a particular genre of movie.
We often forget that everyone is entitled to their opinion as much as we are entitled to ours. We often get to convincing someone out of their likes when they don't match ours, then be it something as trivial as movies, music, career, car choices, or something that is personal like the person someone chooses to be with. So, next time you find yourself convincing someone, why not look from that person's point of view?