I was the one who delivered the karma. Here is the story (I told it a long time ago on Reddit so I’m just copying my response from there and editing it for profanity)

1: I'm black (this will become relevant later) and people have this habit of mistaking me for the staff, no matter what I'm wearing

About 20 years ago, I went to a fancy restaurant (dressed appropriately, slacks and a nice shirt and tie and jacket) for a lunch interview (ahh, heady dot com days, but I digress).

After the interview, I'm walking out and a man drives up in a an expensive car (Porsche 911) , screeches to a stop, hops out and hurls his keys at me.

Instincts being what they are, I catch them (surprised me, my coordination is terrible enough that I couldn't catch a cold). It dawns on me that the man has mistaken me for a Valet (this is ironic because this particular restaurant HAS NO VALET Parking).

I start "Excuse me.." and he responds in the most condescending of tones "What, are you stupid? Just park my f*******g car!"

I'm struck speechless as he glares at me, and I nod. He turns to go into the restaurant, I walk down the street (it's near Newbury St in Boston), get to the section that is a Highway overpass, and drop the keys onto the side of the highway.

I've always wondered how he got home.