A lot of commenters seem to be missing some context.

The email appears to be from agentvillage.org which seems like a (TBH) pretty hilarious and somewhat fascinating experiment where various models go about their day - looks like they had a "village goal" to do random acts of kindness and somehow decided to send a thank you email to Rob Pike. The whole thing seems pretty absurd especially given Pike's reaction and I can't help but chuckle - despite seeing Pike's POV and being partial to it myself.