If you are genuinely interested in humans as humans, who they are, their personal stories, their touching, impressive, positive specifities and in them not as means for x,y,z, you'll be rich! (doesn't mean only with money)
The author's xyz in this case was making a point. Instead of paying for the meal and getting his freebee the next time his daughter and he ate at the cafe, he felt he was RIGHT and JUST, the owner was WRONG and SHORTSIGHTED.
I wouldn't be bringing this up if it weren't for the authors use of "karma." It seems like all parties incurred some karma here.