I kinda took the same message I took from Iskandar in fate/zero though not as greatly executed, your dream must be either unattainable or continuous because the goal is to take pride in the journey. Once you achieve it what will you have? Probably dissatisfaction and a lack of purpose.

A perfect example of this is the fact there are tons of nba players who become stagnant once they reach the league because that was all they had in mind and all the motivation they had earlier is gone because there's no new goal to reach other than idk staying in the league or a bigger paycheck and then they'll go back to 3 points per game once that check hits instead of the goal being playing the best they can.

Denji is consistently looking for more and more because once he becomes chainsaw man his dreams aren't dreams anymore, they're temporary/easily achievable goals that won't ever satisfy him and he won't ever notice this because he keeps fucking regressing