So says he increasingly sees customers in fine-dining restaurants bullying waiters for no good reason.  

If the air conditioning is too cold, it's not their fault, he points out.

"Lately, a lot of people in Hong Kong have a lot of negative energy about them," So says.

And one way they vent is to pick on service staff.

Good etiquette isn't merely dressing like James Bond or holding the door for someone, So says. It's an attitude - and it's all about confidence, respect and communication.

"When you see people who are confident, they often have good etiquette as well; people who are not very confident are often the ones who don't look you in the eye, or look awkward."

With Hong Kong's economy reliant on financial services and the tourism and hospitality industries, minding your employees' manners also makes good business sense, he says.

So, who has been providing etiquette coaching since 2008, launched the East-West Institute of Applied Etiquette last month, in response to growing demand from corporations, retailers, banks and hotels. Among his clients are executives from the mainland who want to boost their confidence for meetings with those from other cultures. As Chinese businesses grow, more want to expand beyond the region, he says.

"Brands like Lenovo; they're a big contender on a global scale. People who work for companies like that have to promote an image that is commensurate with the brand."

Other clients are from companies entering the mainland who may not be familiar with its social and cultural nuances. For these people, poor etiquette could be a deal-breaker. "When you're meeting Chinese companies, a lot of the time no one speaks until the most senior person in the room has spoken," So says.

"They have this hierarchy and it's adhered to quite strongly. That's something to be conscious of."

A consultant friend of So's recalled a gaffe by two visiting Australian associates.

"They walked into the room with clients and there was a huge conference table. These two young guys came in, took their business cards and tossed them down the table. It was like dealing cards. After the meeting she pulled them aside and said, 'Boys, you're in Asia now. You can't do that.'

"In Asia, you have to exchange cards with two hands; look at the person's card afterwards, take an interest in what the person does, and their position. I find that's a common mistake."

So also helps brands looking to improve the service quality of their frontline staff. One large European retail brand wanted to ensure staff were top quality because it had international executives visiting.

"These brands want to make sure the person who comes into the store, whether they buy anything or not, will walk away with a service experience that will make them want to come back," So says.

Local business schools have also recognised the importance of etiquette; So coaches students from four local universities. Although young people today are technologically savvy many have lost the ability to communicate face to face, he says.

"I talk to HR people and they tell incredible stories about people who come in and don't know how to behave. They don't know how to look you in the eye, or answer basic interview questions one should know."

So's university workshops cover areas such as business introductions, dining etiquette and dressing for the workplace. In the autumn, he runs courses on résumé cover writing; in the spring, he coaches students on interview techniques. "That's when the companies come on campus to interview, so they want us to prep their students."

Many people ask him questions on how to dress, probably because it's something inherently visual. "After they see all my slides, they'll come up and say, 'Is what I'm wearing OK? Is the tie colour OK?'"

He recommends wearing only a white or pale blue shirt for business meetings because bright colours are too attention-grabbing. A black suit should be avoided because black is best worn only for very formal events such as weddings and funerals.

So, who is also a host on the TVB lifestyle show, and an events emcee, says he brushed up on etiquette "on the battlefield". A few years after passing the bar exam in New York, he returned to Hong Kong and worked in the private banking division of a US investment bank. It was when he left that job, in 2008, that he got the idea for etiquette coaching.

"I found that among the people I met - the bankers, the clients with more than US$10 million in investible assets and sometimes interview candidates - there was so much margin for improvement," he says. "I started thinking it would be nice if I could do something to help these people out."

Although the institute does not sell itself as a dining etiquette school, these courses are popular because they are a lot of fun, he says. So avoids the rigid "Swiss finishing school" formalities of measuring the distance between knife and fork, and participants ask lots of questions, he says.

"A big one would be, 'Am I allowed to pick my teeth at the table?', or 'Am I allowed to put make-up on at the table?' For both, it's definitely a no. If you're going to pick your teeth, you have to cover your mouth, but I would definitely say go to the bathroom.

"And I've seen women who, at the end of the meal, take out a make-up box - we're not talking a little powder pouch, we're talking a box with those layering trays - and start putting on their make-up right there at the table. Ladies, your bathroom is nicer and bigger than the men's room for a reason. Yours is called a powder room because you have toilets plus a nice room with mirrors for you to brush up."

Clients also often ask him what they should do if their waiter is rude. If you're eating at a cha chaan teng, you're out of luck, So says.

Well, what about that waiter in the fine-dining restaurant you want to bark at because he has been sloppy?

"Very politely, confidently, call the manager over and say, 'Excuse me, we would like another server please'," So says. "You don't have to give any reasons. At a fine-dining establishment, 10 times out of 10 they will not question you. They'll simply say, 'Yes sir', and switch someone over."

At the end of the evening, the manager will probably apologise and ask what the problem was, he says. As simple as that, and an embarrassing situation - and possibly a stomach ache - can easily be avoided.