The deepest principle in human nature is the craving to be appreciated. –William James

According to research, we see people as pleasant if,

A. They are outwardly attractive.
B. They are similar to us in terms of origin, personality or interests.
C. They like us.

Let’s try to understand each in simplest manner with examples.

A. Wherever we go in this modern world, whom would we encounter at first place?
A Receptionist. Almost everywhere without exception there would be attractive women.
Why is it so?

Because there is deeply rooted instinct in humans that we trust the words of attractive people very easily.

This is the first scenario where we fall victim to liking bias.

B. Imagine you moved to the new city. You know nothing about its way of living and culture. Whom would you trust and consult to know about the city. Whose inputs and suggestion you would prefer to follow?

Most probably we all will do the same thing. We will try to find out people from our community or origin (hometown, language, creed, race, nationality etc) nearby. We ask our friend circle and relatives if they know anyone of that kind near our location.

This is the second scenario where we can possibly face liking bias.

C. John like merry so much. and merry crave attention due to her own insecurities.
Merry will overlook all faults of John which she would never prefer to negotiate with in her friend circle.
Why she will do it?

Because John likes her so much.

It would be very very hard for merry to not buy any agenda or offer which John has to offer her.
On top of that, John is giving her what she missed most in her life, Attention.

In marketing terms,
The more we like someone, the more inclined we are to buy from or help them.

If you want Genuine Feedback or Analysis of yourself, Ask someone who are not attached to you in any sense. Never ask your loved ones about how smart you are or how competent you are. They will fall prey to liking bias.

In a way, we should love your enemy for they tell us our faults.

Plain yet most effective Solution to prevent this bias is,

When you are selling something, make consumer think you like them. When you are consumer yourself, Judge the product independent of who is selling it.