Beauty is in the eye of the beholder
Definition 1 of 1
Pro Tip 1/3Subjectivity Highlight
Use this phrase to emphasize that opinions on beauty vary widely. 
She adores abstract art; beauty is in the eye of the beholder.
Pro Tip 2/3Disagreement Softener
It's a polite way to disagree on matters of personal taste. 
You might not like this dress, but beauty is in the eye of the beholder.
Pro Tip 3/3Cultural Sensitivity
Understand that standards of beauty differ in various cultures. 
In some cultures, tattoos are admired. Truly, beauty is in the eye of the beholder.