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Why is theatre a actual thing? How does ones play or acting cause us watchers to stare and gawk at these actors in pure amusement?
Where did the term "theatre" actually come from??

My Random Answer!!

From what I currently know is that theatre was created and given the term "theatre" By people in the times of the old B.C times. These men would dance and do a synchronised dance together, but if one man failed the dance was ruined. It got the name theatre by the way the "stages" looked and how the stage was based on seats and the shape, which now is more advanced, and they currently look like a theatre you would see in today's times. 
Theatre was and is now still created for entertainment purposes to many different viewers. If theatre never existed the theatre world and the laughs that are enjoyed from the show would never be there we would laugh at T.V yes but no true acting and dialogue from real actors who put on many emotions to do their part in the show.
A way the actors acting may get the viewers to stare in amazement and gawk at them is the way they are truly playing that part in a great way to affect the audience and the emotions the facial expressions and the costumes if you truly practice and try your best, you can do it!. Those are ways that actors get their audience to be amazed and to enjoy the show, to stare to gawk to think "hey these actors have amazing talent" or "these actors as I can see are putting a lot of effort into their character and to this play". That's my random answer to you byeeee!!!

Love Yours truly
-Suicidal Erica! Bye! 💙🐋