A recognisable situation
An entrepreneur wants to buy a particular property. After weeks of negotiation he says: "This must be it." As a result, he starts accepting conditions he would reject with any other property. The desire has become so strong that it guides his judgment.
A question to consider
How much freer can you choose if you know you can move on even if you do not get this?
In plain words
You may strongly desire something. The test is simple: can you still think clearly if you do not get it? If the answer is no, the desire may be controlling you more than yourself.
The nuance
Do not make a judgement here about money, ambition or possession. It is about freedom of choice, not about what someone may wish.
Explanation in own words at What truly moves people and the speaker's compass. Book p. 17; speaker's compass p. 5.
Practice this insight