The idea is that you can have a belief and derive emotion from it without ever consciously acknowledging the belief.

Aaron had some deep-down, partially-formed belief that he worked harder than his partner Jim, without even knowing it. That subconscious belief led him to be passively aggessive.

By acknowledging that belief and the associated anger, he can now look at the belief logically and solve it. Does Aaron truly believe that he is a harder worker than Jim, and is that a problem? If so, he should talk to Jim about taking on a side job or more chores, or maybe break up with him. If not, then he should consider what might be fueling that belief. For example, Jim might work his ass off practicing and performing and cooking good food, and perhaps Aaron could do more to appreciate that.