Final answer:
Cialdini finds the low-ball technique's ability to create commitment before revealing all costs as the most impressive aspect, leveraging people's desire for consistency after initial agreements.
Step-by-step explanation:
Robert Cialdini identifies the power of the low-ball technique primarily in its ability to create commitment before revealing additional costs or conditions. This psychological strategy leverages people's desire to maintain consistency after making an initial commitment.
Thus, when Cialdini refers to the most impressive thing about the low-ball technique, it is its ability to secure that initial commitment even if the final terms of the agreement are less favorable than initially presented. Essentially, the low-ball technique is seen as impressive because of its efficacy in influencing people's attitude, ideas, and behaviors, creating a commitment to a decision before its full implications are known.