"I wish they'd stop being so stand-offish with each other. Maybe if we get lucky they'll make a mistake tonight." Said by her father as the two mains are out on a date. Ren's reaction is priceless.
The Hot Springs Episode, in which Juugo has an Imagine Spot where he pictures Kazuma and Ayano becoming close, a curtain pulls and we see a bed in the background. Later, Juugo learns that Kazuma's father has gone to that exact same resort, sparking the exact same Imagine Spot, up until the zoom out to the bed, which is instead a wrestling ring.
Also from the Hot Springs Episode, Kazuma and Genma getting into a rapid-fire fistfight every time they meet. Complete with implications that maybe, FINALLY, they might develop some respect for each other. As would be the typical shonen trend. It doesn't happen.