A festive first clue from The Times today:
Use our Cryptic How To Solve guide to find out more about why the answer to this is NEGATIVITY.
‘Bad attitude’ is the straight part of the clue.
‘Say’ is synonymous with ‘for example’ or, in other words, ‘eg’. When this is found ‘during’ a Christmas scene (or, nativity) we discover another the answer (nEGativity)!
I hope that explanation has left you in good spirits.