According to a study in the Journal of Personality, discipline and self-control both correlate with happiness and life satisfaction. In the study, 414 adults completed a survey where they were asked about their habits pertaining to impulse control, overall life satisfaction, and current emotional state. The team of researchers then assessed data from a previous study in which 205 adult participants were asked about their emotions at random moments while using smartphones; they were also asked to make note of any desires or impulsive behaviors they were experiencing and whether or not they acted on them or resisted. The data from both studies was compiled and the conclusion was that self-control dictated more satisfied results in people's lives.
There is something to be said of those who avoid shortcuts; they execute a set of strict goals and stick to the program. People who have a high measure of self-control do not waste time trying to figuring out quicker ways to complete a task. These people focus on what makes sense, regardless of how much effort is required, thus avoiding conflict as a result. And in turn, are generally happier than their impulsive counterparts. To explain why this is the case, the researchers conducted an additional study. This time, they found out that people with a lot of discipline tend to avoid issues associated with poor planning and problematic behaviors. Those with exceptional impulse control don't waste time finding easy ways to complete tasks and hardly give into desires on a whim.
The takeaway is that people will likely experience a higher rate of happiness and success if things such as exercise, diet, or even finances were approached with a conditioned state of mind. Failing to plan is essentially planning to fail. A regimented lifestyle with a strict set of habits will lead to a much easier life in the long run.