When we have a lot of work to do, slow consistent effort spread over a longer period of time is the most efficient way to achieve our objective. In the case of spiritual development, this is really the only way to make progress.
If we were thinking that we would be able to overcome the strength of the defilements, greed, anger and delusion by applying short term effort alone, then we will have to re-evaluate our approach. If we try to suppress our anger and our desires, this is something like a person trying to stop a moving train. We can never muster enough strength to do that.
By contrast, if we put in less effort but we do so on a regular basis, we can accumulate exponentially more work. Over time as we seek to experience more moments of mindfulness, we will find that we begin to achieve a greater understanding of the nature of all phenomena.
Soon after he enlightened, the Buddha began teaching by explaining the middle way. In essence, we can achieve clarity only when we have learned how to work consistently without pushing too hard. With this clarity, we will then know what actions we need to take to bring us towards happiness and away from suffering.