I tend to give the" lecture", the one about other people who are much worse off
than they are. The one that usually ends with, "now get your shit together and get on with it".
Hugs are ok too. just before delivery of the get your shit together line.
I don't pander to princess like behaviour.
my world famous choc chip cookies
works a charm
If I know they are feeling down I know that any effort will help.
Something as little as breakfast in bed or just sitting throough a chick flick without snoring can improve their mood.
Oh and always answering the dodgy questions like "would you do that for me" that relate to idiotic hollywood premises in these type of movie.
Of course if she is having her period its different, heading for cover and treading carefully are sensible too.