Alphonsus Liguori was a promising young lawyer in the eighteenth century. 'Promising' is perhaps not the right word; he was generally recognized to be brilliant, passionate about his profession, and extraordinarily difficult to beat in a court of law.
In 1723, however, he was leading counsel for one of the sides in an important lawsuit between a Neapolitan nobleman and the Grand Duke of Tuscany, involving hundreds of thousands of ducats. He was confident of winning, having checked over the evidence multiple times, and gave a brilliant opening speech. Almost immediately, however, the opposing counsel said, "All of these arguments are a waste of breath; there is a document that destroys your entire case."
"And what document is that?" Liguori asked, with some heat.
And the counsel handed him a document he had read dozens of times; but as he read it then and there he realized that he had misread it every single time, and that the actual phrasing had almost the opposite meaning he had read into it. He conceded the case, and was so crushed that the opposing counsel and judge actually felt they had to console him for the loss; in particular he felt that it looked like it was a deliberate deceit on his part, and that his career was ruined. He left the court certain he would never return again. After a few days he did recover from the blow, and regard the humiliation as sent from God to deflate his rising sense of self-importance. But he never went back to court; instead, he joined the Oratory, eventually going on to found the Redemptorists, become the greatest of the Catholic casuists, and be canonized a saint. But that all started with the difficulty of interpreting a text.