There are many who would avow that stereotyping is unfair and rude, if not just plain Wrong. Since you and I have already discounted this false prophet, he of Wrongness and Rightness, we are already semi-freed of this fascinating deception.
What is stereotyping? It is placing the man before you into a subset of other men, grouped by their overwhelming characteristics. Taken as a whole, men fall into groups, and after meeting a sufficient number of them, and performing analysis on them (for which the human brain is pre-wired for), you have a very nice technique that, used with care, can be infinitely useful for quickly executing rules, within your own ruleset. Take care to periodically review your own rules, and adjust them for your own benefit, using logical tools to tweak them, for optimum results (depending on how you term optimal results you will of course tweak your rules differently).
An aside: why am I talking about tweaking your rules when your consciousness is a figment, a very interesting figment there is no doubt, but a figment nonetheless? Well, its rather simplex actually: this excellent figment works best when used as if it were true, as if free will was indeed the object of reality. Quaint, isnt it? This is predetermination at its best.
When you meet a man who has a university degree, say a business degree (you have no doubt met many of this type, of the middle class), who now, facing the world at 24 has no clue for what he is about to do, you easily group him into his apparent category, and use your pre-compiled scripts on him. The bytecode for these scripts is already running in your interp. You know that if you comment on the job market, with a quick nod to propriety, you will gaily communicate and will indeed form a bond. With the right body language you will no doubt become his friend. As the chameleon you shift, changing with the winds of circumstance, and you rule.
A girl of 17, interested in pop culture fits a mold. A man of 45 with 3 children living in the suburbs, with graying and thinning hair fits a mold. Understand that mold and you understand 80% of the person.
Every once in a while you will meet a man who does not fit any of your given molds, you running stereotypes. Meet more of his kin and you have a new type, meet no more of his kind and you have an abberation. These can be dangerous or interesting, or both, mostly depending on your wiring.
I am indeed interested by these kinds, and are usually only loyal to these, who are most often termed 'free thinkers', or freemen.