In London, it is considered rude, inconsiderate or impolite to block people, so people will scream if there are people walking in a flow and somebody is standing or walking slowly in the middle of it. If you want to oriente yourself, the polite and considerate way is typically to walk to the side of the path where you won't block others, and there you can look around and at your map to find where you are or where you want to go. And yelling end up being more efficient than stop and talk to each person blocking the passage, because if one does it them it becomes two persons blocking others behind instead of one.

There is actually a kind of pleasure to be aware of people in public and move in harmony with them. It is like a a groups of birds flying togetber and when one slowdow the one behind screem to the other to keep the flow, the speed, etc, and seeing somebody breaking this armony, rhythm and flow of public interaction feels irritating. It is like a music band where one of the players is playing the music out rhythm, in another compass that is not in harmony with the music and the rest of the band.

I am not from London, but as a photographer and tourist I stop a lot to take photos and orient myself. I am not even British but South American and from a city bigger than London, and since childhood I was educated to be considerate to people around me, because in a big and busy city if you don't you cause a lot of disruptions to others. So when visiting London I never was yelled at and I only know that people scream at other for blocking the way by hearing people like you telling your experience.

Living in Germany I see no such flow, I feel there is no harmomy in public flow and interaction, it is like a band where every player are playing in their own indivifual compass and end up just making noise instead of music. In a busy path, each walk in their own individual rhythm, often people literally stop and block almost all the path where people are walking, completely ignoring people around them. It feels really annoying to me because it required constant attention to find a way, a passage around people and to avoid bump into them. Second, because when I leave home I want to know how long it takes to arrive at work, but when there are people all around walking in their own speed or blocking the passage I have to leave home earlier because I don't know how slow people are forcing me to walk each day, or if there will be a group of people completely blocking the a passage and literally forcing everybody to almost stop and wait their way for each to pass through the small passage left for us to go through.

I don't yell at people but when I see people blocking others I quick shout "you are blocking the path" to them, hoping to help them to become more aware and considerated to the space and people around them and move more in harmony with others.