Assuming the best in others brings out their best; Assuming the worst in others brings out their worst. The psychology of this is clear: when one is innocent but is perceived as guilty, one will be tempted to lose the desire to ‘remain’ innocent, for it is viewed as fruitless.
But when one is guilty, and is perceived to be innocent, the guilt will inspire them to change their ways and be the person they are perceived to be. Exposing your ‘perception’ of someone, to that someone, will make or break the trust of that relationship. This is the moment where one will be inspired or wounded by perception.
Therefore, it is better to think the best of others and be wrong, than to think the worst of others and be right.