I would not concern myself regarding the ship's Captain and other senior officers. There will be photos of all the ship's senior officers near the mid ship elevators, I believe on deck 7. I'm sure the Captain will be fine and pleasant should you happen to meet him. Passengers really don't interact with the Captain. He does show up at large events, usually on formal evening, to address the crowd.
Passengers interact mainly with the cruise director and assistant cruise directors. They are the ones that run passenger activities. Passengers also interact with their cabin steward, DR waiters as well as bar tenders and bar waiters. All of them are nice. They don't last unless they are.