Discipline should be one of the cardinal virtues (though it is related to fortitude which is one). Discipline is the ability to work, though rewards seem slim and to continue in a course of action when the fun and the initial glow begin to fade. It is the the skill that creates accomplishment, builds careers and marriages and yes, fine stamp collection.
Many people come to our hobby and don’t progress past the stage where they acquire a nice set of albums and the group of stamps that are most readily available for the countries that they collect. They enjoy our hobby, until they move on to their next diversion. Disciplined collectors maintain their interest even when the collecting gets tough, when new acquisitions are infrequent and the time spent looking for what is needed does not always seem worthwhile. Discipline is the skill needed to pursue advanced educational degrees and is found in most of the successful people in every field. This is probably why the philatelic world contains so many collectors who are so accomplished in their professional life. Discipline in a personality trait, encompassing everything you do. And it can be learned. If you are like most people, you probably feel that you are somewhat disciplined but could be more so. Setting reasonable collecting goals and then attaining them is good discipline practice that will transfer to the rest of your life.