For instance, ties with big pictures identify males. The males are lower class. Paisley ties mark upper-class gentlemen. Paisley ties are neat. One study of clothes reveals this.
Students apparently react to symbols of authority.
Students work harder for some teachers than for others. Students work harder for teachers who dress in suits. Students don't work as hard for teachers in shirt-sleeves. And you may want to move up the corporate ladder. Then be prepared for this.