The second half of a man's life is made up of nothing but the habits he has acquired during the first half.
-- Fyodor Dostoevsky
I've been listening to a series of talks by Pema Chodron. She talks a lot about Habituation, which is Ego based: We repeatedly do something, think something or repeat an action, and it gets stronger. We reinforce the action through repetition. Of course, the stronger the habit becomes, the more it controls us, and often the angrier we get.
One aspect of habituation also comes in to reinforce our opinions and prejudices. Strictly spoken, habituation is not negative; in fact it can be extremely positive. Note that the Tibetan word for meditation means "habituation." However, when negative emotions repeat, habituation can cause exponential growth of problems.
If we just look at the results of racial and religious discrimination and hatred, it is sadly obvious how extreme opinions can arise and create havoc, simply because they have become habitual. Once something is a habit, we do not question our behaviour anymore, it becomes automatic and extremely hard to change.
Habituation
