Is the word "unbelievable" positive or negative?

Do you get a positive or negative impression when “unbelievable” is used as an answer to these questions?

1 – How’s work going?... Unbelievable.

2 – How’s your mom doing?... Unbelievable.

3 – How’s the service at the new restaurant?... Unbelievable.

4 – How’s the food at the new restaurant?... Unbelievable.

5 – How did the family reunion go?... Unbelievable.

6 – How did the job interview go?... Unbelievable.

7 – How are the kids doing?... Unbelievable.

8 – How was your vacation?... Unbelievable.

9 – How was your flight?... Unbelievable.

10 – How’s your project going?... Unbelievable.