Pettiness of mind, ignorance and presumption are the cause of stubbornness, because stubborn people only want to believe what they themselves can imagine, and they can imagine very few things.

We must accustom ourselves to the follies of others and not be astonished at the foolishness that takes place in our presence.

The foolish acts of others ought to serve more as a lesson to us than an occasion to laugh at those who commit them.

Often our good deeds make enemies for us, and the ungrateful person despises us on two counts; for he is not only unwilling to acknowledge the gratitude he owes us: he does not want to have his benefactor as witness to his thankless behavior.

Nothing can tell us so much about the general lawlessness of humanity as a perfect acquaintance with our own immoderate behavior. If we would think over our own impulses, we would recognize in our own souls the guiding principle of all vices which we reproach in other people; and if it is not in our very actions, it will be present at least in our impulses. There is no malice that self-love will not offer to our spirits so that we may exploit any occasion, and there are few people virtuous enough not to be tempted.

We learn as much by others' failings as by their teachings. Examples of imperfection is just as useful for achieving perfection as are models of competence and perfection.

When an opinionated person starts to challenge something, his mind shuts out all that could clear up the matter. The argument irritates him, however just it might be, and it seems that he is afraid of discovering the truth.