The practice of compassion increases our capacity to care. It reinforces charity, empathy, and sympathy. It is very good exercise for your heart muscle.
But when you move toward others with compassion, you are likely to bump into some common attitudes, just waiting to close your heart again. The usual suspects are judgment and all its associated "isms": racism, sexism, ageism, classism, and nationalism.
On a personal level, your compassion is sabotaged by feelings of ill will toward others: spite and malice. These feelings, and others arising out of emotional wounds and personal pain, are actually symptoms indicating that you need to have compassion for yourself. What do YOU think?