Almost all Klingons, Romulans, Cardassians, Vulcans act as one. They almost always have the same hairstyles and clothing. Most of these societies aren't sustainable, especially the Klingons.
DS9 fleshed out Cardassia quite a bit. I wish other races got the same treatment. Klingons went from bad ass fighters, to a warrior culture, to everything it about being warriors, to caricatures. My favorite version of the Klingons was in STVI. Those seemed like real in depth people.