We like people best if they start off cool or indifferent to us and warm up over time. We dislike people the most if they start off being friendly to us, then ice us out.
This helps illuminate something that I have noticed, but never had the right vocabulary to describe. I have a number of friends who are incredibly enthusiastic about the people they meet. Each new person is like a new adventure, and is viewed through rose-colored glasses. Then, as they get to know the new person better, they become disaffected, and the relationship suffers.
The principle SBK describes explains both jaws of this insidious trap. My enthusiastic friends often have their enthusiasm reciprocated, but as time passes and they begin see the flaws of their new friend for the first time, their enthusiasm cools. Not only does this cause them to cool to the new friend, the very same thing happens on the other end of the relationship, as the new friend perceives the cooling and thus their own feelings cool.
Because I combine sincere enthusiasm with a level-headed “let’s see what happens” attitude towards the new, I neither put myself on the path to disillusionment, nor set myself up to disillusion those that I meet about my own merits (or demerits).
This wasn’t any intentional strategy on my part, just an acknowledgement that like everyone else, I’m not a flawless snap judge of character, and that acknowledging and accounting for this produces better results.