Say you had a ten-year-old daughter who was really into fashion. Say she liked high fashion in magazines, but was cultivating a kind of boho punk aesthetic for herself. Think miniskirts over jeans, tank tops over long-sleeved shirts, mis-matched socks, red patent leather ballet flats, and wacky hairstyles.
Say most of the time she was pretty cute, and she was also amenable to reasonable suggestion, which you took as the opportunity for fashion lessons (not that you were qualified for such, but you do have a little more experience). For instance, you could tell her that a tiny t-shirt over a huge long-sleeved shirt looked too bunchy and weird, but a small t-shirt over a large long-sleeved shirt is fine, and she would get the point that proportion matters.
Say your opinion was really important to her, and you knew that and respected it, and were determined to be supportive of her fashion choices, even when you would never choose them yourself (which would be totally reasonable if you were, say, a fortysomething mom).
Say one day your daughter came up with an outfit that you hated. Like, it made your skin crawl. But there was no rational reason for your hatred, just that she looked like a scarecrow. (Say the outfit was a long flounced denim skirt over jeans, and one of her dad's shirts that was 2/3 as long and twice as wide as she was, belted with a crocheted scarf, over a long-sleeved shirt.) Say just looking at her put you in a bad mood.
What would you do?