I like when people kinda start to get it…. but they don't fully get it yet.
Like "oh man, just you wait...it's coming."
They can tell that he's good, but they can never possibly imagine HOW good.
It adds to the comedy immensely as it makes it feel like a looney tunes skit. Even baring witness, first hand, what Saitama is capable of everyone either tries to play it cool, play it off as a fluke and forget about it, get unreasonably angry, or simply achieve extreme denial bordering on insanity. Saitama is a tacky caped bald man with a stoned out face so everyone always assumes he's a normal citizen or the lowest of the low in the hero rankings. Literally turning expectations on their head.