Well, I just talked about idealism being the cause of some self-pity.
The other causes of self-pity tie in with the other question about separating ourselves from the rest of the world and nature, If we do not have a broad enough view that we are part of something bigger, then when difficulties arise we tend to focus just on ourselves and that difficulty, rather than seeing it in relationship to something else, that it's not as big as we think.
This idea of isolating ourselves from nature can bring it about, not wishing to open to Dukkha can bring it about, or the rejection of Dukkha, which is very easy to do as most people want happiness in their life. They feel that if they protect themselves by not seeing Dukkha, then somehow this will protect them from it. But actually as we learn to open to Dukkha, we do not get so upset when it arises in our life and so there's less chance of self-pity to arise, because we realize it's just part of life. And, we're not saying, "oh, poor me" when it happens, because this is the nature of human existence.
Understanding more about the nature of human existence and seeing Dukkha being a part of that existence helps protect us from getting too upset when Dukkha arises in our life.
So one of the antidotes as I said is to open to life as it is, which helps us to let go of self-pity. We're not so self-absorbed.
And actually, opening to Dukkha will lessen many difficulties, so it's not just an antidote to self-pity, it's also an antidote to many things. This is because if we're able to open to Dukkha, Compassion to arise, Compassion is the wise response to Dukkha. Compassion is the key for many things in this practice. So by learning how to open to Dukkha rather than pushing it away, one is able to open to the unselfish emotions, which lessens the tendency towards selfishness and opens us to the possibility of understanding the nature of things as they are.
Many of the techniques that we teach can assist you to open to Dukkha in a way that is easier for you to do. If we try to open to Dukkha without having the emotional maturity to do so, that is building sufficient power of the unselfish emotions, Dukkha can be overwhelming.
We need the power of the unselfish emotions and wisdom so we don't take Dukkha personally and make ourselves into the victim of it. Unselfish emotions also helps us to let go of fear.
Sometimes, if we're lost in self-pity, our mind is very small and the smallest things tend to irritate it. But when the mind is more expansive and open with the unselfish emotions, its capacity is enhanced, it can then open to great suffering, because there's not so much 'me' involved in it and 'me' suffering from it. That is why there are four unselfish emotions, and Equanimity helps to strengthen Compassion.