Pleasant feelings last as long as we enjoy them.
MN44:24.2: “Pleasant feeling is pleasant when it remains and painful when it perishes.
Painful feelings are pleasant when they end.
MN44:24.3: Painful feeling is painful when it remains and pleasant when it perishes.
Painful feeling do cease eventually.
DN34:1.4.27: Renunciation is the escape from sensual pleasures. The formless is the escape from form. Cessation is the escape from whatever is created, conditioned, and dependently originated.
However, painful feelings will persist as long as we insist on craving pleasant feelings.
MN44:25.2: “The underlying tendency for greed underlies pleasant feeling. The underlying tendency for repulsion underlies painful feeling. The underlying tendency for ignorance underlies neutral feeling.”
Struggling to escape from painful feelings by pursuing pleasant feeling perpetuates this endless cycle. The escape from this cycle is to relinquish the tendency to hold on tight:
MN143:6.1: You should train like this:
MN143:6.2: ‘I shall not grasp sight, and there shall be no consciousness of mine dependent on sight.’ …
MN143:6.5: ‘I shall not grasp sound …
MN143:6.6: smell …
MN143:6.7: taste …
MN143:6.8: touch …
MN143:6.9: thought, and there shall be no consciousness of mine dependent on thought.’
If painful feelings last longer than pleasant feeling, then there may be benefit in examining such continued existence.
MN38:17.8: Craving is a condition for grasping.
MN38:17.9: Grasping is a condition for continued existence.
Grasping at pleasant feelings, wishing them to continue creates suffering. Pleasant feelings always vanish and that vanishing is painful. It remains painful as long as we grasp at the memory of the pleasant feeling that is now gone. Wanting pleasant feelings to continue after they are gone is painful. So, by not grasping at the pleasant feelings, unpleasant feelings will disappear on their own.