What Metallica Songs are the Best For Setting The Mood?

I was getting ready this morning and I interesting thought popped into my head: What Metallica songs do other people think are the best for setting different moods? So, I thought I'd come here and ask you guys.

What Metallica songs do you guys prefer for...

Happy and silly moods?

Sad moods?

Angry moods?

Romantic moods?

Spazzy moods/Brain burnt moods?

etc.