What does it take to make a metaphor?

My best friend told me I was New Jersey,
Where the only thing that matters more than our malls,
Are our shows in the city and down the shore;
Our late night/early morning diner talks,
When we consume each other,
Over black coffee and a piece of chocolate cake.

My first boyfriend said “baby you’re cancer”, after knowing me for a week.
He told me that everything I touched I destroyed:
You have the power and talent to make things seems bad,
You ruin people’s lives with those shy smiles;
They’ll never be how they used to be,
Not after you reach out to them.

My mom tells me that I’m an eighties movie.
The John Hugh’s type, never like Richard Linklater’s,
Where emotions run like water paints,
Boys fall in love with the girls social circles reject;
Girls walk on tight ropes to be with them,
-- the ending is always happier than real life.