How about –

1 – “It’s not your job to worry about that.”

2 – “Do you have data to back that up? Your intuition doesn’t mean anything.”

3 – “That’s not how the government does things.”

4 – “You don’t know everything that’s going on, or you wouldn’t suggest that.”

5 – “Let’s put that in the parking lot (the garage, the back burner, etc.) and get back on topic.”

6 – “Technology can’t solve everything, you know?”

7 – “How can you even suggest such a thing?”

8 – “They will never agree to that” or “IT will never allow that.”

9 – “Don’t you think you’re being a little negative?”

10 – “Just because you saw a good presentation at a conference doesn’t mean it can work here.”