“If I agree, why should I bother saying it? Doesn’t my silence signal agreement enough?”

The fact is that there is a strong motive to disagree: either I change my opinion, or you do.

On the other hand, the motives for agreeing are much more subtle: there is an ego boost; and I can influence other people to conform. Unless I am a very influent person, these two reasons are important as a group, but not much individually.

Which lead us to think: There is a similar problem with elections, and why economists don´t vote .

Anyway there is a nice analogy with physics: eletromagnetic force are much stronger than gravitational, but at large scale gravity is much more influent. (which is kinda obvius and made me think why no one pointed this on this post before)