Honestly, if I ever had any relations with people like Mayumi and Sayaka, I'd be swinging hands daily. Being an asshole is not a character trait, its a fatal flaw.
Actually, I would like to add more now that I've read further. Mayumi is just a straight bitch. Single old woman can be used as a funny character trait, but this is......so aggravating. She does all this petty shit but since it's fiction it's just brushed off as her "quirk". Sayaka's bad, but Mayumi is just terrible. Why are you so hateful? Why are you so petty? Why do you beg for sympathy when your actions prove you aren't worthy of it? This whole rant was triggered by chapter 46. My man's does some research to make the girl he likes happy, and she just eats it as a reflex. How utterly disgusting. If I was there on the last page of that chapter, I'd be kicked out of the boarding house for fatally wounding a tenant. No joke. I would literally be unable to contain my anger and contempt.