Why people talk to you
A shared table, a question in line, or a walk to the same viewpoint is enough to meet someone. You do not need to force a social plan or sign up for every activity at the hostel. When you are alone, people talk to you because there is an empty seat and because you are not already closed inside a conversation.
That does not mean every trip has to become a round of introductions. Some of the best talks last a coffee and end there. The value is not in collecting contacts. It is in the place becoming a little more concrete because someone told you the name of that street.