As the series goes on, many characters, to some and many degree, actually become "flanderized" (maybe because of the manga's increasing comedic tone over time).
Yamaoka becomes much more of a jokester, Ohara and Koizumi become more dramatic and hysterical (despite originally starting as calmer and more stoic), Tomii becomes more of a loud-mouthed manchild who endangers his own job and company quite a lot of times, and more.
Wow, here it is, the Okinawa cuisine stand-off arc! For those who don't know, the whole arc was actually adapted into a TV special movie back in the day, and it didn't change much of the arc's story when it was aired.
Was an entertaining arc overall, learned a lot about Okinawan dishes here that I'd like to try someday.