Question about not words but gesture,
About flipping off:

I often see someone gives someone the finger in U.S. movies. (Emma Stone does it to Ryan Gosling in the beginning of LA LA LAND). It is a familiar sight in a sense. Whereas, I have heard it is an extreme provocative action.
One of my acquaintances from U.S.A said "You are shot if you do it."
Other said to me "You don't have to take it so seriously."

How is it actually ?

Question

Question about not words but gesture,
About flipping off:

I often see someone gives someone the finger in U.S. movies. (Emma Stone does it to Ryan Gosling in the beginning of LA LA LAND). It is a familiar sight in a sense. Whereas, I have heard it is an extreme provocative  action.
One of my acquaintances from U.S.A said "You are shot if you do it."
Other said to me "You don't have to take it so seriously."

How is it actually ?

Answer

Everyone interprets it differently, but in general terms, I would say that it's an extremely rude gesture and you shouldn't do it unless you intend to start a fight or a very intense argument at least. In some instances, people do it as a joke, but only among VERY close friends. Otherwise, it is extremely insulting and you should avoid giving that particular gesture. It's equivalent to saying "fuck you!" or "Go to hell!" if you were to express it in words.

Answer

I got it can lead to physical fights, thank you Moeen-san.

Answer

Duplicate.

Answer

It is really bad and can lead to physical fights, unless you are friends and just joking around.