If the Sole Survivor tells the waitron that they would like a table, he will escort them to the open booth and, once they sit down, he proceeds to ask them how one would like to be served. There are four options: mashed, diced, charbroiled or, if a Charisma check is passed, one can tell him they are not hungry. If any of the first three options are selected or the Charisma check is failed, the waitron and Cook Handy will become hostile and attack. At this point, it seems that one can defend themselves without any repercussions.
If the player character passes the Charisma check, the robots will continue to run the establishment. The next time the Sole Survivor takes a seat, the waitron will sell various food items.
If the player character leaves the booth without having been served, the waitron will call out that he hasn't served them yet, and both he and Cook Handy will become hostile and attack. At this point, it seems that one can defend themselves without any repercussions.
Other interactions
Upon entering the diner, the waitron will offer the Sole Survivor the last remaining booth. All of the other booths are occupied by skeletal remains which, when asked, are simply referred to as "satisfied customers."
Inventory
Apparel
Weapon
Other items
Notes
When choosing either the mashed, diced or sliced dialogue option, the Sole Survivor will always respond "Wait, what?"