Josef's bad habit was that his desire as a collector was too intense.
If there was something he wanted, he had to have it, no matter what. One could even say that Josef's political skills as a wise king were honed to satisfy his collecting habit.
To fulfill such a strong desire legally, he needed to be ready with ample compensation. Even a king, who could exert his authority, or rather precisely because he could, would face rebellion if he ruled too arbitrarily. Only by governing justly could he get away with pouring the country's treasury into his hobbies.
"Your Majesty, this is an extraordinarily rare item. The merchant who sold it to me claimed it was the first of its kind ever created. For reasons unknown, they also asserted that it could not be recreated, even if dismantled. While I would love to present it to you, I believe that might be impossible."