Very much so. Being quiet and having a girly appearance, people often underestimate my intelligence. In school, my math & science teachers were often shocked to see I was one of the top students. As an adult, I bet few people would peg me as having a lot of intellectual interests. To many, I look like a girl who likes to shop & get her nails done. My Ne-aux nervous randomness doesn't always help (it says "airhead" to some people).
People may also underestimate my friendliness, and write me off as aloof or snobby. Many seem to think I am dull, or a goody-goody, or very serious because I am shy at first.
On jobs, I am underestimated for being quiet also. Extroversion is associated with so many positive traits and introversion with so many negative ones that you are almost seen as "incompetent" at first when you're an introvert. I usually earn respect over time and employers really grow to value & depend on me, but not enough will give me that chance based on their bias towards people with a reserved demeanor.