For those downvoting: Just as an example here's Google's Material "designers" doing a study with 800 people to figure out that yes, text fields must look like text fields, and learning literally nothing from it: https://medium.com/google-design/the-evolution-of-material-d...

As a bigger example: almost every single CSS framework decides that color and contrast are for suckers and makes many controls (and especially text inputs) with barely visible gray-on-gray colors.