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]
(..) Thank you. Sir. -Thank you. -Thank you, sir. No wonder he was in such a foul mood. My mistake. Can I give you a lift home? That would really send him over the edge. I'm afraid I'm not that cruel. (..)2006 Casino Royale