It is very easy to be "swayed" by others.
People with strong opinions will share them quickly ... and often!
If a couple of people are of the same opinion then there is a momentum, and that can pull others along into a herd mentality.
"Too often we... enjoy the comfort of opinion without the discomfort of thought." John F Kennedy
In the normal course of our daily lives there will be many such moments when this kind of "peer pressure" really doesn't matter.
It might be about mundane things like characters on a TV show, or which color of beige is best on the wall (really ... once it is done you will likely not be able to tell the difference!)
Other times it is important to keep your own counsel, understand the situation and make your own call.
If you are in a leadership role, or aspire to be in a leadership role it will be important that you demonstrate an ability to make sound decisions, and the fortitude to not be swayed by popular opinion. That does not mean being inflexible; it does mean making measured decisions and informed opinions.
The herd mentality is rarely a good way to reach important decisions.
The "herd people" are typically loud, opinionated, easily influenced and see only one side.
Ask lots of questions.
Try to understand the situation objectively.
Don't leap to conclusions.
Block out the "herd people" ... you already know who they are.
Make a habit of thinking for yourself, not just taking a story at face value!
"It is the mark of an educated mind to be able to entertain a thought without accepting it." Aristotle