red herring's

what is a red herring? 

a red herring is something a director will use to mislead the audience or distract the audience entirely until it is finally revealed which should shock the audience 

a technique known with red herring's is a unreliable director a great example of this can be seen in the joker where we are shown that arthur is going out with a girl called sophie until we are shown it was all just in arthurs mind when sophie tells him that he is in the wrong apartment with a load of the shots previously shown removing sophie from the scene showing it was all in arthurs mind 

example