Be hateful and nice alternately, till completely exhausted (4,2,3,4)
I believe the answer is:
blue in the face
'nice alternately till completely exhausted' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'be hateful and' is the wordplay.
I cannot really understand how this works, but
'be' could be 'face' (facing is a kind of being) and 'face' is found within the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for blue in the face that I've seen before include "Furious" , ""You can argue till you're ____"" .)