@codinghorror should consider this. Besides the biases mentioned above, tech folks have been urging Facebook and the like to start minimizing likes, and, although I think the psychology of getting likes on your Instagram post is rather different from getting likes on a BBS post, there’s still the thrill of dopamine chasing.
Further, to expand on OP’s comment about biases, I find that I have an aversion to clicking like on a well-liked post, because “it doesn’t need it,” and visa-versa for a post with no likes. I believe a study found a similar effect in Amazon reviews, where people rated more towards the extremes than they really felt if they were going against the grain, in an attempt to “correct” the rating. In any case, this leads to ratings that are not actually reflective of our views.