Here's my two bits.
Call it vibe or buzz or whatever you will. What you're feeling at Café Mondegar in Colaba on a Saturday night is a convergence of collective emotional energy. And emotion, like the common cold - is extremely contagious.
But how did that energy get there in the first place? Let me try and use a well-loved equation to explain it: E = m c squared
Where E = emotional energy or 'buzz'
M = Mood
C = confluence X 'charge'
Sounds vague, huh. What is this 'charge'.
Well, charge is different things at different times, but essentially it's heightened expectations of ... something.
At a stadium before a cricket match it's the anticipation of seeing Tendulkar batting, of hoping he won't be out for a duck and the uncertainty of not knowing what the outcome will be. Except that you have 8 hours ahead of a jolly good time.
At a 7 bungalows it's the anticipation of bumping into interesting people, places to shop, eat and hang out. 7 bungalows or Colaba Causeway or Leicester Square are essentially hubs which attract diverse individuals - some trendsetters and some good old ordinary folk.
The Origin of Buzz
It might start with a single such individual setting up shop - one where the business and culture in some way collide ie generally, a trendy new restaurant, clothing shop, music store, lounge bar - something that is instantly recognised to have that intangible quality called 'cool'.
Purely on word-of-mouth, the 'cool', good-looking, confident patrons will start coming in. All of those attributes are generally available to those with time and money to spend, whose concept of life has moved beyond survival or worrying about the future - to a constant search for 'what's new and exciting'. By definition these people are mostly young or at the least youthful.
Not every cool business instantly results in the development of a hub. It takes time - and suitability of location. Eg Lokhandwala/ 7 bungalows with its vicinity to so much 'new money' has just what the buzz doctor ordered.
As more and more interesting establishments open up, the place becomes a hub - and attracts more and more interesting people. All of whom come with a certain air of expectancy 'of having a good time' which charges the atmosphere. When that charge develops critical mass - the air acquires a buzz.
Over a longer period of time, it's not the original trendsetters ie the commercial or cultural establishments which maintain the buzz - it's just the people. Colaba Causeway- though stagnant in terms of new and exciting things to do is buzzing just because of the folks who are attracted to come hang out there.
A large number of backpackers - thanks to the Lonely Planet guidebook recommendations - and street hawkers who sell cheerful and cheap imbue excitement and newness - an experience that's different every time.
A tale of 2 cities
At a macro level, cities have a 'buzz'. Because they create heightened expectations. The migrant from Bihar arrives in Mumbai having heard that 'no one can starve to death here'. The streetlights/ paved roads/ tall buildings - all build up in him the anticipation of a 'good life'. Or at least one that is better than what was left behind.
The MBA who comes to the city to take up his or her first job has a similar set of expectations about 'Bombay life'. The important thing is that Bombay some unique characteristics which are not 'Marathi', 'Gujarati' or specific to any one community. Or India, in general. eg People in Bombay are always in a hurry - which in itself might be creating some 'buzz'.
Similarly, a city like New York attracts people from all over America - and the world (ie confluence) - all arriving with a heightened sense of expectation of something. 'Making it big', drinking in culture, being more 'free' than
they were in Athens, Georgia where all 3000 residents meddle in each other's lives from baptism to funeral.
Can it be generated?
Knowing all this, can one 'create' a buzz? Perhaps. Singapore is trying hard.. though honestly it's not as buzzing as a HongKong which got there through the process of natural evolution.
I think the best you can do is try and assemble the elements and hope they spontaneously combust. The challenge is to go a step further, and figure out how to light the matchstick.