People have jobs, schedules, and apartments across the city, which makes a casual hang-out situation hard to come by.
Annoying adult schedules really don't allow for that kind of romantic simplicity.
That is literally all you have to do to meet people. Not to depress you (or sound like the Princeton Mom), but never again will you be presented with so many single, available options of guys and girls around your age and with your same interests. If you're staying put, try to take advantage of the expanded social network that comes from a core group of people (you and your college buddies) branching out, starting new jobs, meeting new people, etc. Cause it's never again going to be as easy as walking across the quad.
If going to class isn't really your style, there are myriad other ways to meet potential love interests—walking across the quad, for example. You'll probably spend at least one night in the next five years on an air mattress, next to a plastic box from the Container store that's doubling as a nightstand, lying awake to the sound of an old man's phlegmy cough, in some distant, distant part of the city.
And if you like each other, you plan for a second one.
And a third, and a fourth…You thought you were broke in college, and maybe you were—except you probably also had a nice-enough dorm room, an all-you-can-eat cafeteria, and a social life consisting mostly of free parties and campus events.
When it comes to dating, the early twenties are a tricky time.