You seem to enjoy being in the office after hours, left to your own devices. It’s fun, and you get time to be in your head to work on your own thing. The space that you’re in—the noise from the bars below, the quiet inside the room when nobody is there, the little amount of light peering in from the streetlights outside creates an atmosphere in which you’re able to do great work.
When you’re trying to work, you should recreate that kind of space no matter where you are. Move to a pleasant spot to do your job, your reading, your writing. If you’re distracted, move somewhere else. Much like sleeping, putting yourself in a good physical place is a proactive way to make yourself happier and more peaceful as you work on whatever your labor consists of.