A mere nod and smile at the person sitting diagonal to you at the library table can work wonders. In the library where unzipping a backpack sends a roar of soundwaves hurtling into scores of stressed students, this simple nod is advantageous, for speaking in a library is, as we all know, strictly forbidden. You know that phrase, "A picture is worth a thousand words"? The Nod, as long as eye contact is made and it's accompanied with a smile, has the ability to convey even more than that. It can mean some or all of the following: "Hi ... how are you doing? ... Do you mind if I sit here? ... That textbook looks heavy and way intense, so I won't bother you ... I'm stressed about mid-terms, too ... I'll make sure my phone's on silent so I don't embarrass us both ... There really isn't a way these chairs could be more uncomfortable, is there? ... Does this tapping bother you? ... (and with a longing glance out the window) I too wish I could be out there enjoying autumn in Utah, but no, professors just like to interfere with life. I feel your pain. ..." By the time you leave the library, you're practically best friends and you haven't spoken a word.
Who ever said you needed words to communicate?