God “shows no partiality to nobles, nor regards the rich more than the poor, for they are all the work of his hands.” (Job 34:19)
A priest is not permitted to choose who he “likes” and doesn’t like. We are here to serve Christ and His sheep. When one of those sheep comes to us to receive the sacraments or advice on formation or for spiritual guidance, we can not refuse to provide these to them solely based on whether or not we “like” the person. This is not the same as providing the sacraments to a notorious sinner, but even to them a priest has certain obligations.
As far as the world is concerned, as Christ taught us, while His sheep are in the world, they are not part of it. This does not negate our responsibility to bring the Gospel to those in the world.