Be careful to reject always movements (like vexation, discontent etc.) that bring back confusion or depression. One cannot always help these movements coming, but one can reject them when they come; the more they are rejected, the more difficult it becomes for them to recur—or, if they recur, they hold only for a moment and then drop away. To entertain them means to give them a chance to cover the true consciousness once more.
Ref: Letters on Yoga Vol. IV