How a little pain makes something more attractive

These findings do not mean that people enjoy painful experiences, such as filling out their income-tax forms, or that people enjoy things because they are associated with pain. What they do show is that if a person voluntarily goes through a difficult or a painful experience in order to attain some goal or object, that goal or object becomes more attractive.

Source: Mistakes Were Made (But Not by Me): Why We Justify Foolish Beliefs, Bad Decisions, and Hurtful Acts