Don't therapists work best with certain kinds of clients/problems? It depends on their guiding ideas.
I helped develop the idea that all problems have one problem underlying them--shame for feeling ashamed. That jawbreaker won't make much sense unless you work with me or read some of my articles. But consider that I've been using this idea as the heart of my work for 40 years and have shown to many clients and other professionals that, if you solve this underlying problem, all other manifestations of this problem--from alcoholism to teen angst--fade into the background.