"There is a way of practising mental development (meditation) with regard to all our sensations or feelings, whether happy, unhappy or neutral. Let us take only one example. You experience an unhappy, sorrowful sensation. In this state your mind is cloudy, hazy, not clear, it is depressed. In some cases, you do not even see clearly why you have that unhappy feeling. First of all, you should learn not to be unhappy about your worries. But try to see clearly why  there is a sensation or a feeling of unhappiness, or worry, or sorrow. Try to examine how it arises, its cause, how it disapears, its cessation. Try to examine it as if you are observing it from outside, without any subjective reaction, as a scientist observes some object. Here, too, you should not look at it as 'my feeling' or 'my sensation' subjectively, but only look at it as 'a feeling' or 'a sensation' objectively. You should forget again the false idea of 'I'. When you see its nature, how it arises and disappears, your mind grows dispassionate towards that sensation, and becomes detached and free. It is the same with regard to all sensations or feelings."

What the Buddha taught - p.73