If there is no suffering, there is no way that your child can learn how to understand and to love. We can not grow up as the good human beings.
Only when you are in touch with suffering, that you can cultivate understanding. When you understand someone, you don't hate, you don't get angry at him anymore. And love is based on understanding. If you can not understand, you can not love.
If you don't understand the suffering and difficulty of your partner, you can not love him, love her and make him or her happy. That's very plain.
That is why love is made of understanding. And understanding is first of all, understanding of suffering. And you have to understand your own suffering first before you understand his suffering or her suffering. Understanding suffering gives birth to compassion that has a power to heal and to transform. And that is the kind of energy that we need the most in the world.
We have to produce understanding and compassion because these two items can not be found in the supermarket. They don't sell that. They sell only the things that can help us cover up the suffering.
Thay said, "Only when you are in touch with suffering, that you can cultivate understanding." Understanding means insight, and mindfulness and concentration are essential in order to attain insight. In this sense, Thay's words may mean that if we are in touch with suffering (if we understand the root cause of suffering), we can stop thinking and be mindful. If so, it is the same as my experience.
Thay often teaches us that conscious breathing or walking enables us to be mindful (to stop thinking and return to true self). But I feel that this instruction is supplementary and the true method of being mindful is by understanding the root cause of our own suffering through insight.
So, suffering is very precious. Suffering is the foundation of understanding which generates love. That's why we should not run away from suffering. We have to face the suffering.
In order to understand the root cause of our own suffering, we need to be fed up with it and strongly want to change ourselves. This intention and determination gives birth to insight. In the process of looking deeply into the suffering, we can be automatically mindful and concentrated.