Thor’s line ‘He’s a friend from work’ was not scripted in Thor: Ragnarok.
The line originated from a child from the Make A Wish Foundation who had suggested it to Chris Hemsworth during a break between filming. Since the director, Taika Waititi encouraged its actors to improvise lines during filming, Hemsworth gave it a try.
As a result, the line became one of the best Marvel lines in history. Social media blew up during the release of the official Thor: Ragnarok trailer and it was all thanks to one child.