The middle stage of of treatment is generally the longest, most productive, but also when clients can lose interest and terminate without a planing to.
As a side note, I really liked the example they shared in the textbook. A good realistic case example.
Exploring the reality—the real relationship—will help the worker adjust to client needs. A client may be justifiably angry with a worker for numerous reasons. Perhaps he was inattentive, unempathetic, or preoccupied. Something as seemingly slight as answering the phone during a client’s session may feel like a lack of empathy and produce a strong reaction from the client. You may not hear the reaction right away, but subsequent sessions will provide clues. The skilled worker pays sharp attention during the middle phase to the client’s verbal and nonverbal behaviors. It is completely appropriate to mention, for example, that the client seems less talkative, or more edgy, or that something seems different. This is not to be confused with confrontation. Direct confrontation can be offensive and angering to a client, with the exception of those who have or are participating in recovery programs where confrontation is the norm. It is much better to gently comment that it seems hard for the client to talk about something, or to respond to your words, than to rush headlong with an interpretation such as “You are angry that I’m talking about your past.” Interpretations often feel like wounds, especially if they are made too early in the work. And they can often be incorrect. It is more appropriate to explore and let the client come up with the meaning for herself.
Cooper, Marlene G; Granucci Lesser, Joan. Clinical Social Work Practice: An Integrated Approach (p. 29). Pearson Education. Kindle Edition.