One reason why people give up is that they lose the reason for why they started out in the first place. I watched the documentary Child of Our Time, which featured a mother who stopped yelling at her child to sit still, because she cannot remember why she wanted her child to stop moving anymore. At one point, I wanted to give up on God because I stopped remembering the purpose for trusting in Him and for even believing in the first place. And then when the primary motive for the race comes rushing back, you pick up where you left off.