You probably know one of the "box people." Whenever they meet someone new, the box people try to identifying which box the person belongs inside. "What do you do?" That's the first question to determine a label. Once they know the "box" (based on class, politics, religious affiliation, etc) then they can related to the new person in the way appropriate to how they've learned to treat folks with that label.
Now, suppose they meet someone living outside the set of predetermined boxes? Well, then thefundamental box-people belief is challenged: Everyone belongs in one of the tidy little containers. This challenge will be met with greater and greater demands to "get inside a box! I don't approve of non-box-affiliated lifestyles."
Ever had that feeling? The feeling of being treated as a prepackaged echo of bias and unjust expectations.. rather than as a unique person?