The 2nd Noble Truth tells us that the cause for our suffering is craving - the desire that holds on to or pushes away experience. Letting go brings ease and freedom.
The mental Factor of Vedana (pleasure, pain and neutrality) arises in every moment. Through the practice of Mindfulness we can separate our deep sense of contentment no matter the pleasure or pain aspect of experience.
The Buddha taught that the cultivating of wholesome states (Kusala) creates conditions for awakening.
This talk explores the importance of this cultivation, its place is Wise Effort and how to "maintain and increase" these states as he encouraged.