*** Air Traffic Control and Cocktail Parties ***
Imagine a cocktail party at which all the guests (aircraft) are blindfolded. They are not allowed to talk with one another and must listen attentively for navigation instructions from the bartender (controller). This is to provide separation between guests so they don't bump. Bumping would be serious as drinks would be spilled.
A guest must listen to all the bartender's instructions, even though most are not relevant. An instruction intended for a particular guest must be quickly acknowledged and obeyed by the guest.
Many guests want to approach the bar (airport) for another drink. The bartender's instructions will place them in a single-file line with sufficient spacing to be really, really, safe. After all, the guests cannot see each other or communicate with each other. This seriously limits the flow of booze, and the party is boring.
The poor bartender is stressed out, and occasionally his voice fails (comm systems failure) or sweat gets in his eyes (radar failure). All the guests must then be rerouted to a cocktail party in an adjacent room (it happens). This is very scary for some guests with half full glasses (fuel).
Not a fun party.
At my kind of cocktail party, all the guests can see each other and navigate fluidly with an occasional "Excuse me, behind you." The only bumping is voluntary, and for reasons beyond the scope of this discussion.
If the bartender disappears, the guests help themselves. The party is not doomed.
The bartender is smiling because his job is only to pour drinks on a first come first serve basis. In fact, everyone is smiling, and some are laughing out loud.
William Cole On cocktail parties, NY Times 3 Dec 72: "A hundred standing people smiling and talking to one another, nodding like gooney birds."