I use the library a lot, but in a weird way I actually find it quieter in a coffee shop. Libraries are mostly quiet, but the one group of gossiping people pretending to study becomes that much more annoying since you can make out every word. Background noise in a coffee shop is more ambient and generally constant. I also don't get outraged when I hear someone speaking since they aren't breaking a rule or making me think they never saw the episode of sesame street where kids learn to be quiet in the library.