question:  Why is Si so astonished when there is a real bartender working the bar?
context: They also had a banquet for him, complete with speeches by such bigwigs of the Department of Space Exploration as Academician Lofting Gubelin and Doctor Hans Girard-Perregaux. In common with recipients of gold watches of a score of generations before him, Si Pond would have preferred something a bit more tangible in the way of reward, such as a few shares of Variable Basic to add to his portfolio. Possibly somebody like Doc Girard-Perregaux might be horrified at the idea of living in a mini-auto-apartment ... not realizing that to a pilot it was roomy beyond belief compared to the conning tower of a space craft. Even as Si listened to their speeches, accepted the watch and made a halting little talk of his own, he was grinning inwardly. Girard-Perregaux grunted his sarcasm and dialed a glass of iced tea and tequila. Gubelin, half angry at his friend's argument, leaned forward to snap rebuttal, but the other was wagging a finger at him negatively. Automation being what it is, only a fraction of the population is ever called up. He was drafted into the working force reserves, served his time, and is now free from toil for the balance of his life. Girard-Perregaux was wagging his finger again, a gesture that, seemingly mild though it was, had an astonishing ability to break off the conversation of one who debated with the easy-seeming, quiet spoken man. If it is admitted that our organization has degenerated to the point that we haven't a single pilot, then it might well be that the Economic Planning Board, and especially those cloddies on Appropriations, will terminate the whole Department of Space Exploration." "You must realize, my dear Lofting, that our Si Pond is nothing more than a latter-day sailor, with many of the problems and view-points, tendencies and weaknesses of the voyager of the past. "Unfortunately, our present-day sailor can't be separated from his money quite so easily.
output:  He didn’t expect it. It’s a job that is normally automated, and it’s shocking to see a human working it.
options:  He hasn’t been talking to people, and Si is caught off guard seeing someone face to face again after so long.  He’s never seen a bartender before, nor been in an establishment that has one.  He was in his thoughts considering his money, and was caught off guard.  He didn’t expect it. It’s a job that is normally automated, and it’s shocking to see a human working it.