Over the past year working from cafés in a dozen cities across three continents, I have developed an informal anthropology of café working culture. The unwritten rules vary enormously, and getting them wrong is a quick way to feel unwelcome.
In some cities the laptop-on-table is normalized. In others it marks you as a tourist or worse — someone who does not understand how the space is meant to function. Knowing the difference is usually a matter of observation.
Berlin cafés are among the most welcoming to laptop workers, with many establishments explicitly catering to the city's large freelance and remote working population. Research from a long-running community thread on the topic indicates that WiFi is fast and free, and nobody bothers you about how long you stay.
Paris is the opposite. Working on a laptop in a traditional café feels transgressive; the cafés that tolerate it are marked as such, and the experience is different from the social cafés where locals spend their afternoons.
What strikes me most is how quickly local norms develop, seemingly spontaneously, in response to new technology and working patterns. A decade ago none of these distinctions existed. Today they are strongly enforced, usually informally.
The best approach in any new city is to observe before setting up. If most patrons are in conversation, you are in a social café. If laptops dominate, you are in a working café. Do not try to convert either into the other.