We just returned from a few days dining in SF and were reminded how much difference a caring managerial presence makes.
At Citizen Cake, the absence of their former manager was noticeable throughout the dining room. We asked after her when the meal was over and was told that she was moving to the East Coast and was waiting tables somewhere else but our waiter wasn't sure where. The service we experienced wasn't horrendous, just sloppy and neglectful. Chatting with co-workers rather than attending to the tables, and a return of the attitude that almost kept us from returning quite some time ago.
For our last meal we decided to try A16. In contrast, they were extremely welcoming, helpful with The Sardine, and as we were being taken to our table we saw the former Citizen Cake manager. She was waiting there until her move to Charleston, SC, later this year. When we told her about our experience at her former digs, she said "I hate to hear that. That kills me." She was also quick to point out that it wasn't just her, that lot of people left at the same time, and that the whole team is responsible for the experience.
Presence on the floor is crucial. How to get others to maintain that presence when the owner is gone or the manager is absent is the Holy Grail of the restaurateur.