We have all experienced this effect with a complicated name. It is also called a "cognitive bias," but that phrase has a whiff of info-gypsyism, so we'll just call it an effect. If something emotional or important happens to you, something new, you will notice it much more often in the world. For example, you or a friend bought a car—you'll see it everywhere for a while. Switched from Android to Mac or iOS? Now everyone around you has these phones. Planning to move to another city? All bloggers on the internet are moving, just like you.

Why is this dangerous? In business, as soon as you start testing a hypothesis, you will notice confirmation everywhere if you are an optimist, or refutation if you are a realist or pessimist. And you will draw wrong conclusions.

How to deal with it? Only data-driven decisions. Don't just test a hypothesis; define the necessary metrics in advance and decide what to do next before conducting the experiment. For example, before a problematic interview, decide that if there are 7 confirmations out of 10 calls, you will launch a landing page and paid advertising to test whether sales will occur. If there are fewer confirmations, change the target audience and test again. The main thing is, after conducting 10 interviews and getting 6 confirmations, don't start bargaining with yourself—follow the planned course.