Pain and Pleasure

here is one peculiarity associated with pain and pleasure, which I
would like to share with you. The more we think of our pains and
suffering, the more they go on increasing. On the contrary, the more we think of
our pleasure, the lesser the pleasure we derive.

Is there not a hint in this phenomenon which can be extremely useful to
us in the conduct of our life?

Source: P. Rajagopalachari, Chapter "Duty," The Spider's Web, Vol. 2,
p. 243.