Coffee, Pizza and TCP

If I send a request from a client to a service, what's the difference between a response and a TCP ACK.

Well it turns out it's all about coffee and pizza.

Typical Scenario

Me: Can I have a flat white? (Request)

Barrista: Sure (ACK)

Barrista: Here's your flat white mate - I'm in Australia (Response)

Me: Cheers (ACK)

TCP RETRANSMISSIONS

Me on dodgy cell phone: Hi can you send me a 7-inch thin crust Il Padrino (Request)

Nothing

Me: I said can you send me a 7-inch thin crust Il Padrino (TCP Retransmission)

Pizza Guy: Sure (ACK)

Pizza Delivery Guy: Here's your pizza (Response)

Me: Thanks (ACK)

RESPONSE TIME

Notice that the time to serve me the coffee was from Request to Response not to the ACK. Same with the pizza.

Coffee, pizza, TCP - it's all the same.