So there are several things the captain can do which significantly improve the passenger experience.
The first is to communicate, frequently, candidly, and sympathetically, about delays. It's really frustrating to be kept in the dark, particularly when the status of the departure affects the likelihood of making an onward connection, or making an important appointment at the destination.
Another is to turn off the seatbelt sign as soon as it's safe. Sometimes it's left on for five hours of absolutely smooth flying. That's a really uncomfortable place to be as a passenger, particularly if you didn't have time to hit the restroom before take-off.