Ditch Starbucks and work at the library
In my (biased, but well-founded) experience, it comes down to a question of whether I'd rather be distracted by a cute girl or an old man getting reprimanded for looking at dirty pictures.[bg: I really like libraries - worked at one in the suburbs in high school and have since moved to the city, which exaggerated the weird bits]One thing that's worth noting: if you're on a college campus, a great place to find some legit quiet time is in departmental libraries, especially the social sciences.