We can do whatever we wish to do provided our wish is strong enough. But the tremendous effort needed- one doesn't always want to make it-does one? ... But what else can be done? What's the alternative? What do you want most to do? That's what I have to keep asking myself, in the face of difficulties.
Buddha's doctrine: Man suffers because of his craving to possess and keep forever things which are essentially impermanent... this frustration of the desire to possess is the immediate cause of suffering.