Salad Dressing

If you just put oil and vinegar in a jar, and you don't shake it, you do not get salad dressing.

You have to put energy in.

Supermarkets think very, very carefully about what things they put on the shelves that are under your hand while you queue for the checkout. Milongas should think just as carefully about what the room looks like when you enter it; about who is coming, and who is already there; about how the people in it see themselves, see each other, and try to make themselves comfortable. Humans are social, extremely sensitive to all kinds of complex signals, and you cannot expect them to put them aside, especially as most of them are processed unconsciously.

The information they need to form a community - however briefly - can be exchanged with time, or it can be provided, within certain limits, by leadership and proper shaking of the jar.