yes / no
these lines from some TV series make me confused:
1. A: are we good?
B: nope, we are good.
2. A: I think it's such a terrific thing that you …
B: no, it is.
For answering 'are we good?', why is it 'no', not 'yes'? and how comes when you what to agree with someone, you say 'no, it is.' instead of ' yes, it is. '?