In the "Schumpeter" section of the current edition of The Economist there is coverage of Happy Clappy.
That is essentially the belief system that positive makes for happy and happy is always good. Currently both human resources policies in some organizations and interaction with customers embody happy clappy.
For example, at work, the environment is structured to motivate employees' experiencing a sense of well-being. There may be even be a Chief Happiness Officer. Those on the front lines serving customers - in-person, online, or on the phone - are trained to exude positive feelings. Those range from smiles (over the phone it's the smile in their voice) to wishing the customer a happy rest of their day.
It's debatable if happy clappy significantly improves employee performance or the bottom line. Also, observers wonder if all the energy invested by employees in happy clappy can precipitate burnout. When I handled the hospitality industry's calls to the front desk, that smile in the voice wore me out. I might not have quit so early in the game if I could have just managed the calls in a business-like way.
Lawyers in law firms probably don't have to fear that this movement will become organizational policy.
After all, the system is essentially up or out. That isn't a fertile setting for happy clappy to take root. In interfacing with clients and pitching to prospects, the worst of happy clappy - smiles and over the moon optiism - would be counterproductive. The law business is about solving problems, many of them serious. A positive tone could be a good fit. But not much more than that. Clients and prospects are reassured by caution. It is all too easy winding up in prison, paying out big in a verdict, fine, or settlement, or becoming the victim of bad press.
One lawyer, shrewd about persona, told me the best way to present yourself both internally and externally when practicing law is with a poker face.