does One Punch Man get any serious story arcs at some point? or is it like fun and stupid funny all the time?
theres numerous numerous other characters that arent Saitama who get focused on. Saitama himself is a rather lazy, picky superhero when it comes to decided what he intervenes into.
The battles and struggles of the likes of; Genos, and Metal bat, and hell even the villains like Garou equals where the drama/seriousness comes in.
hell in this Hero Hunt arc, Saitama barely been featured in the action, and its been the most action heavy arc.
No, it is first and foremost a comedy. Sataima, while technically "da bes evur," serves only to cast a light on action series and show how ridiculous they are. His almost deadpan mannerisms serve to highlight how ridiculous a lot of comic book heroes and villains (both eastern and western) can really be.
Saitama represents the west, specifically America, overbearing with power without even having to try, capable of defeating anything that comes his way and never has to take anything seriously, earned his strength through proper training
Genos and the rest of the super hero organization represent Japan, unnatural evolutions of people trying way too hard to be ranked #1 when the real #1 could easily get to that rank if he actually tried, pretending they could change and save the world when really Saitama (America) cleans up after everyone with flawless victory, often with Saitama making jokes at everyones over grudgingly convoluted tryhard backstories: "20 words or less!"
>serves only to cast a light on action series and show how ridiculous they are
It works in reverse. All the "serious" drama and kickass action scenes are meant as the comedic foil to highlight the humor of the series. They're not there to be the meat of the series or compete with your battleshonens. Every arc is the same joke, usually at an escalated scale, and that's the fucking point.
fact of the matter is; its light and easy to watch. and goes through like 3-4 chapters of the manga/WC per episode. So watching the anime feels like you got through a lot of it, and didnt really waste anytime, even if it lacked a form of sustenance you may crave ina show.
and thats ok.