David Brin has an interesting hypothesis: indignation is addictive.
We know that the same chemical and other pleasure triggers and reinforcement processes that lead us to crave food, sex, and other things we need to survive, are often mislead by things we neither need nor really want to surive (such as heroin, cocane, cigarettes, alcohol, and similar drugs), and in fact these triggers can be self-induced through purely mental activities, such as meditation, prayer, and other religious activities.
Brin proposes that we look to see if indignation can provoke this sort of response as well. Having been involved in many an Internet flamewar, I find this quite plausible myself. It's ridiculous, I know, but I do somehow enjoy getting upset with people and flaming them. (I'm hoping that I now better recognise just what might be going on in my brain with this behaviour that I'll be able to control it better.) The beauty of this hypothesis is that, if true, it well explains so much of what goes on on Fox News. Rush Limbaugh and Bill O'Reilly, as they twist facts to upset themselves, are no different from the crack addict who will do almost anything to get another fix.
An interesting thing about this idea is, as with drug additions, how far it might lead you into behaviours that, given your background, you really ought to revile. The behaviour of Gretchen Carlson could be an example of this. That she would claim to have to look up the words "ignoramous," "double-dip recession" and "czar" is astonishing enough, but that someone with an academic background that includes an honors degree in sociology from Stanford University and studies at Cambridge is otherwise almost beyond comprehension.
But damn does it make for amusing television.