Serving a large group of drunken people at a table isn't always fun. They can be loud, they can be disruptive, and they can be generally difficult to deal with. Most waiters and waitresses have a coping strategy to deal with those situations, and it seems this one got hers just right.
Whatever she did to entertain and appease this group, she definitely made a strong impression on at least one person at the table, who wrote her a long note of thanks. We hope it was backed up by a large tip!