It can be merely aggravating, terribly frustrating or even be fatal. It is a terrible feeling when someone, or indeed many people, don't believe you. It was as common to the films of Alfred Hitchcock as the beautiful blonde.
Poor Margaret Lockwood. No one would believe her elderly companion existed in The Lady Vanishes (1938). Pity Cary Grant. Those evil spies would not believe he wasn't also a spy in North by Northwest (1959). Imagine innocent Henry Fonda, suspected, arrested and convicted of a hold up he didn't commit in The Wrong Man (1956). Likewise Derrick De Marney wrongly accused of murder in Young and Innocent (1937). And what about Robert Cummings, believed to have committed sabotage in Saboteur (1942). And I haven't even gotten to Jimmy Stewart in Rear Window (1954) or Gregory Peck in Spellbound (1945).
To be wrongly accused, or have your claims of witnessing something disbelieved, touches a central human fear. It is to be alone, and to be suffering an injustice in that isolation. It perverts our basic relationship with society and thus can literally drive us insane.
Hitchcock explored this, and the elemental desire for people to prove themselves. The need to be redeemed became primal in these characters and their efforts thus bordered on the super human. In most cases the characters were "ordinary" people to begin with. Grant an advertising man, Fonda a musician, Stewart a photographer, Cummings a factory worker, De Marney a writer, etc.
This provided two elements to the story. One is that none of us are immune to a seemingly random accusation – innocents are regularly being cleared by DNA evidence of crimes of which they were convicted. The "It could happen to you" aspect of such stories is a great device to engage audiences and show the arbitrariness of human life. The other element this adds is that we are all capable of great deeds in the name of justice, even if motivated by self interest.
I'm not giving anything away by pointing out that in Hitchcock's films the innocent is ultimately believed and cleared. It is also important to note that it is almost invariably by their own efforts that they are redeemed, not by those of establishment figures like the the police or government. Also, our hero usually benefits from the assistance of a confederate, often a comely blond like Grace Kelly, Eva Marie Saint or Priscilla Lane. We may feel alone as the falsely accused, but in this world we can usually count on someone to help.
It is essential in such stories to restore the world to its proper balance (especially absent this inevitably in real life). Happy endings are generally preferable in films, but in the you've-got-the-wrong-guy fiction I believe them to be a must. Generally speaking, only a nonfiction story should allow the innocent to suffer.
Of course, with Hitchcock we always enjoy the ride, too. There is action, adventure, romance and sometimes even laughs along the way. This softens the hard reality of our character's dilemma and provides the requisite entertainment.
Alfred Hitchcock, the master of the"I-swear-it wasn't-me....."