I believe the main premise of the show, more so than a spy-spoof is the day-to-day interactions of spies and organisations with everyday workplace situations, like Stirfry-day. Plus, the dialogue is very droll.
Archer: I have to go. But if I find one single dog hair when I get back, I'll rub... sand... in your dead little eyes.
Woodhouse: Very good, sir.
Archer: [pause] I also need you to buy sand.
Woodhouse: Yes, sir.
Archer: I don't know if they grade it, but... coarse.