Non-sensical comeback gone awry at work:

As opposed to the usual...
Them: "This is stupid"
You: "YOU'RE stupid"
It went something like this...
W: "Oh man, we missed the cycling class! I was thrown off by the sunlight... it feels like it's 3!"
Me: "You feel like you're 3"
Both: "..."

wait for it... aaaand awkward