The Importance of Data in UX

UX people fail to understand that they need all of this data to understand users. If you're not learning new stuff every day, then your job isn't any fun. Your job is to actually go through the data and find out what the real users of the site are like. You may have experience about something, but everybody has different experiences. That's not your job as a UXer. Don't argue and say that you know the right thing about the users.