We are both identical and contrary

Question

Our head has two parts

• The first part doesn't go well with Paris and should watch what they drink.
• The second part may not be silent but doesn't have anything new to say.
• Together, they are a drop of golden sun.

Our trunk has three parts

• The first part was originally into livestock but these days favors Italian sports cars.
• The second part either likes zigzag shirts or hat & cane.
• The third part doesn't actually call for a rose in teeth.
• It's not usually desirable to get caught in their concatenation.

Our tail has four parts

• The first part is big--but not quite a continent--and likes writing.
• The second part is either a grouch or prestigious depending on who you ask.
• The third part is thankfully remembered for its 4th or 5th.
• The fourth part is known for both saws and forests, both mountains and valleys.
• Together the four parts are invariably an optimist or pessimist, never simply neutral.

Put together, we are both identical and contrary. What are we?

Answer 1

The head, trunk, and tail are each composed of a certain number of 'part's. Each part is a letter and is clued by its word from the NATO phonetic alphabet.

Our head has two parts

• The first part doesn't go well with Paris and should watch what they drink.

ROMEO doesn't get along with Count Paris and should not drink poison.

• The second part may not be silent but doesn't have anything new to say.

Some E's are silent but ECHOS just repeat.

• Together, they are a drop of golden sun.

RE, the musical note which is described as a golden drop of sun in the song Do-Re-Mi from The Sound of Music.

Our trunk has three parts

• The first part was originally into livestock but these days favors Italian sports cars.

ALFA comes from the Greek letter alpha which comes from the Phoenician letter aleph which is the West Semitic word for "ox". ALFA Romeo is an Italian sports car company

• The second part either likes zigzag shirts or hat & cane.

CHARLIE Brown or CHARLIE Chaplin

• The third part doesn't actually call for a rose in teeth.

Some people have a rose in their teeth when they dance the TANGO.

• It's not usually desirable to get caught in their concatenation.

It's not usually desirable to get caught in the ACT.

Our tail has four parts

• The first part is big--but not quite a continent--and likes writing.

INDIA is big but not quite a continent. There is also INDIA ink.

• The second part is either a grouch or prestigious depending on who you ask.

OSCAR the grouch. OSCAR movie award.

• The third part is thankfully remembered for its 4th or 5th.

Thanksgiving is celebrated in the USA on the 4th Thursday in NOVEMBER. We remember remember the fifth of NOVEMBER for Guy Fawkes Day.

• The fourth part is known for both saws and forests, both mountains and valleys.

SIERRA is Spanish for saw. There are also SIERRA National Forest, SIERRA Nevada mountains and SIERRA valley.

• Together the four parts are invariably an optimist or pessimist, never simply neutral.

IONS are positive or negative, never neutral.

Put together, we are both identical and contrary. What are we?

REACTIONS. for every action there is an equal and opposite reaction.