Stephanie, once she is convinced of Number Five's sentience, goes to great lengths to protect the robot. This includes going on the run with him after his escape from the NOVA truck, even though she has no reason to do so. Essentially, she acts as his mother and she'll do anything to keep him safe.
Number Five and Stephanie's dance to the "More Than a Woman" scene from Saturday Night Fever. Goofy? Yes. Totally adorable? Also yes.
When Johnny surprises Newton and Stephanie by appearing alive and well, and explaining that the robot they saw destroyed by NOVA was a double.
Johnny declaring that "I told me" it was wrong to kill.
Short Circuit 2:
Ben's Adorkable attempts to get Sandy's attention is rather sweet.
Ben: If it is O.K. with your Mom and Pop, would you like to go to a malt shop for a cheeseburger?
In the sequel, Ben also starts demonstrating some rather protective behavior towards the robot. Considering he was one of the individuals who built Number Five (with Newton being the other), it isn't that surprising. Like his understandably unhappy reaction to learn Johnny had been hanging out with a street gang all day.
Ben: (catches Johnny covered in graffiti singing the "Los locos" song and angrily shouts) Number Johnny Five! Johnny Five: Uh oh. Ben: Come on! I will clean you up. If you had a mouth, I would wash it out with soap!
Fred, near the end of the sequel selflessly sacrifices his prized silk shirt to try and help a dying Johnny.
To add, the moment Fres understood that Johnny was sentient and not under someone else's control he went from trying to cash in on Johnny to genuinely wanting to help him.
Johnny's reaction to obtaining citizenship. Hammy? Yes. Heartwarming? YES!