I wanted to confirm that is it just a myth or true that when people come back from hajj/umrah they become changed person? Like some people who were bad, after hajj/umrah may be they're repentence has been accepted by Allah and they became good person or whatever the reason may be and vice versa for people returning back becoming mean and cruel? Like we have witnessed some people, and heard aswell, the hypocrite people became even more mean? Does this change happen with people after coming back from ziarat aswell? Because I heard somewhere that if someone experiences a good change in his/herself this means his/her ziarat is accepted,if no change then this means we have to work on ourselves to become a better person?

Heard another saying that humans are not in they're human form in maidan e arafat (depending on their deeds good or bad) in the eyes of those who can see the truth like those whose cover frm eyes is removed like our great clerics ,marjas.and our imam ajfs. Is it so?

As for the first saying, just going to Hajj, Umrah or visiting, man does not change from negative to positive if he does not have a sincere intention to repent and change and to fight the soul. Yes, if he has this intention, God almighty helps him to do so. The one who becomes bad after Hajj or Umrah, he was not good in the first place but he was pretending to be.
Hajj, umrah and visiting are things of worship, obligatory or desirable, and they themselves do not affect the human being by doing them, if he does not have sincerity in the work, such as the prayer that Allah almighty says it forbids from obscenity and evil. We see a lot of People pray, and they commit taboos and this is not a flaw in the saying of Allah Almighty, but because of a defect in man himself. If he was an observer of Allah Almighty, and noting that Allah watches him and that after several hours he will stand in his hands, he will be ashamed to do what Almighty hates.

The second saying is confirmed for the infallibles, peace be upon them, and perhaps it falls to some people who are most loyal to Allah.