Purpose of the Witness Hearing

For a very long time I could not understand for what purpose the witness is being questioned. That is to say, what is the main objective to be achieved as a result of the hearing. No one told us that on the app. As I watched reality, including what I wanted to do myself, I noticed that the purpose of hearing a witness was one of these purposes:
(a) prove the witness wrong;
(b) ask the witness about everything starting with the course of witness childbirth;
(c) prove to the witness that he or she knows less than the representative;
(d) make the witness mad;
(e) change the colour of the witness’s face;
(f) tell the witness loudly before the court and the parties that he or she is lying;
(g) even before the trial, tell the witness that he will be sitting in prison for all the lies he is about to testify;

For a very long time I did not know whether to do everything at once with each witness. Do just one witness do one thing. Today I think the purpose of hearing a witness is this:
make the witness as comfortable as possible so that the words of the witness turn into clear images. This is very difficult. And rare. It requires the cooperation of the court and the parties. But I happened to listen to such a witness a few times: something like “Gymnopedie” Erik Satie.