Saenai Oji San To Ore Sama Yankee Kun

Subaru, a short-tempered young man, is walking one day when he casually saves a dull middle-aged man. The man, two decades his senior, smiles and tells him he's a nice, good boy. For the first time in his life, Subaru is smitten! Even after they part, Subaru can't stop thinking about him.... is this really happening?!