I have been riding the NEC - Northeast Corridor - for about four years, 2 -3x per week. The conductors, for the most part, are not nice. They are rude, abrasive, condescending, and generally in a power mode for whatever reason. These are customer service representatives, and they do NOT act that way. As far as the excuse of the conductors being overworked, I am a surgeon traveling at 4:25 AM from DC to NY and getting back home at 9 PM at night, round trip. I am overworked, far more than these conductors, and in a high stress position. I have chosen to use Amtrak as a cost savings to my company vs other forms of travel. I put up with their behavior at my choice. There are definitely other forms of travel that are more pleasant, faster, and easier to deal with than Amtrak with these conductors involved.
Customer service lessons are necessary. Amtrak wants to increase ridership. One of the best ways to do this is to teach the conductors that riders on the train have a choice - they are not obligated to use Amtrak. Rather than being hostile and rude, maybe consider a smile once in a while or a nice greeting or two. That may create an environment that keeps people coming on back, and build a much better atmosphere for growth and development of the service Amtrak provides.