It's hard to relate to someone who has such wild/extreme 'mood swings'. [=someone whose mood changes very quickly]
She turned down the lights and lit a candle to create a more romantic 'mood'. [='atmosphere']
I'm sorry. I'm just not 'in the mood to talk'. [=I do not want to talk to anyone right now]
(..) MARTY SR: I'm not sure where Jennifer is, Mom. She should have been home hours ago. - I can't keep track... - Fruit! - Fruit, please. - She's in one of those moods. LORRAINE: Aren't you and her getting along? Yeah. Great, Mom. We're like a couple of teenagers. Dad, telephone. It's Needles. (..)1989 Back to the Future Part II