The Joy in the Proccess of Growing

King:

Being down isn’t like you, you’re always so strong.

Saitama:

Well, I’m not going to be getting any stronger. I’ve become too strong. No matter who I fight, I don’t feel anything. I gain nothing from it.
There’s nothing I can learn from anyone.

King:

But, isn’t having that much strength really awesome?

Saitama:

Not having any room to grow means that I can’t enjoy the process of growing. No matter how many monster I defeat inside, I’m bored out of my mind. I never thought being a hero could be so lonesome.

(One-Punch Man, Season 2, Ep 20)