Whenever I read stories about busy and successful restaurants with bad customer service stories, it will always dumbfounds me.
I find it mind-boggling how frequently owners / managers mis-understand the customer service model of restaurants. It is a tough business to make money in already, and taking your customers for granted is a sure-fire way to get on a fast-track to failure. Similar to nightclubs, you often see restaurants that start out strong, get a great name for themselves, and then for whatever reason (success goes to their head), start pissing off customers one by one.
Restaurants, like night clubs, are successful largely based on word-of-mouth. When things are good, there are positive forces, cycles / re-inforcement that build on each other and can take you to the top. But once you start getting cocky and taking your customers for granted, it is INCREDIBLE how this can turn so quickly against you spiralling downward as people tell all their friends about bad experiences. This happens at night clubs all the time - clubs get popular, bouncers / bartenders get cocky, think they can get away with treating their customers like crap, and soon enough, people stop coming in droves, and it shuts down. In today's age of chowhound, yelp, and online access to reviews, it is that much more important to ensure as few bad experiences as possible.
My family has been in the customer service business for many years, and has always understood that even one customer treated badly can grow exponentially. From the owners down to the waiters / waitresses, my parents always emphasized this motto at EVERY team meeting.
"You are not doing your customers a favor by getting them drinks, and serving them. They are doing you a favor by coming into our restaurant. Go into every interaction with them from this perspective, that they are the ones doing you the favor, no matter how busy or successful you are at the moment, and that is the attitude you should always have."
It doesn't matter who you are or how bad of a day you're having - this is the customer service business, and this is your job. Even one bad employee with a bad attitude can severely hurt your business, and as an owner, you need to of course lead by example, but create a culture where without exception, treating customers well comes first.
The best restaurants, even the ones that are always packed, always treat their customers with respect, thank them for waiting, and never take their success for granted (I've seen restaurants with consistent 30min line-ups for many years where the owners will still go out, greet everyone and thank them for waiting, offer them complimentary cookies / desserts / drinks) - this is how you build relationships and good-will with your customers, not by acting snooty.
This isn't a difficult concept, and I'm always shocked at how poorly so many places are at this.