People find many ways to judge each other in life, especially upon first meeting. Your skin, your hair, your clothing; all of these can be factors in how other people form their first impressions.
There's one we haven't mentioned, and it's a big one: the way you speak. Psychologist Katherine Kinzler says judging people by accents and other features of speech can become a significant social justice issue.
She lays out the case in How You Say It: Why You Talk the Way You Do—And What It Says About You. We get into code-switching and other practices in a conversation with the author.