We say yes to people we like

Researchers have tested this many times, in different places, over many years, and they keep finding the same result. This one is safe to trust.

Robert Cialdini spent three years working undercover inside car dealerships, fundraising operations and sales floors, learning how persuasion professionals actually operate. One lever kept surfacing everywhere, so reliable that the professionals barely thought of it as a technique. We say yes to people we like. And the ingredients of liking turn out to be simple: similarity, compliments, and familiarity. His favourite example was the Tupperware party, a sales machine built on the discovery that people buy from the friend hosting the party rather than from a company. He also documented how skilled salespeople hunt for similarity. They notice golf clubs in your car and turn out to golf. They catch your accent and find a connection to your hometown. The uncomfortable part is that the effect works on people who know it is being used.

When someone feels easy to talk to, part of what you are experiencing is similarity rather than quality, and the two are almost impossible to separate from the inside. Put an interviewer in a room with a candidate who went to a similar school, laughs at the same jokes and mirrors their energy, and the evaluation is already contaminated. The interviewer will experience that contamination as chemistry, and will write it down as strong communication or great cultural energy. There is no way to switch the feeling off. The only defence is structural: score the actual work separately from the conversation, and be suspicious when your reasons for liking someone are hard to put into words.

Source: Cialdini, Influence, first published 1984, drawing on three years of field observation and the surrounding research literature.

Draw your own card. It does not take long, and it rewards taking your time.