Yale's student body is diverse and for the most part integrates all kinds of groups and beliefs, working hard towards exposing others to what is out there. Clothing ranges the spectrum, from really dressy to jeans and tshirts to sweats and hoodies - although choices depend mostly on personal style, seasonal deadlines and exam periods can influence this as well. Yale students are from everywhere.
Yes, in lectures it is the most difficult to get to know a professor, just due to sheer size and more of an interaction with the TAs, but even then Professors try to get to know as many students as possible. Classes here are nice in that they bring together people of diverse backgrounds and experiences who eventually grow close due to working together so hard. Students study a lot, almost round the clock, when they are not eating, sleeping, showering, volunteering, etc. They make good use of time, and thus simultaneously motivate other students to do likewise. It's almost contagious. Intellectual conversations abound outside the class, to the point that one can sometimes learn so much more outside the class. It is really wonderful to realize how much you learn through the lives of others.
Master's Teas are awesome - the Master of each residential college invites interesting/famous/cool people. Tuesday 2am - studying, writing, reading, procrastinating on facebook, reading and responding to emails. On a Saturday night - dance.
The best thing about Yale are the people you meet and the opportunities presented, both always things you are enriched by. Telling people one goes to Yale is context specific - for the most part, it is a well recognized name, but not always something easy or useful to give away. While on campus, I like to split my time among class areas, the many wonderful libraries, the dining halls, my college Berkeley and running errands around the remainder of the place. As much as Yale is split among different social circles, it is surprising and comforting to see how these overlap through several people, and how no matter what, Yalies look out for and love other Yalies. Unusual to people who visit, are the many resources we have available to us here.