I wonder if there is any difference between "1" and "2".
1. Don't tell me that faucet's dripping again!
2. Tell me that faucet's not dripping again!
The difference is that the first is commonly heard whilst the second is never heard.
I always hesitate to say 'never' as somebody is sure to pop up and say 'That's what I say all the time'. In this case I'll stick my neck out.