Is it the fashion to get very cross? (4)
I believe the answer is:
rage
I believe this clue is a double definition.
'is it the fashion' is the first definition.
(something fashionable is 'all the rage')
'get very cross?' is the second definition.
'to' is the link.
(Other definitions for rage that I've seen before include "spread rapidly" , "High dudgeon" , "a poetic response to dying light?" , "Fury, passion" , "Fury - fashion" .)