Seeing Kubo appreciate Shiraishi for who he truly is, playfully teasing him without going too far, and naturally encouraging him to come out of his shell; it's all very cute and heartwarming. It's also great to see Shiraishi surprise her every now and then, and try to return her good deeds. Shiraishi's gimmick of being an invisible character is very well used from start to finish, it's always used to great comedic and/or cute effect.
The supporting cast are also no slouches here. I'm particularly in love with how integral Kubo's family are to the main couple's relationship. Her older sister's constant hyperaware teases and her younger sister's slight jealousy is very fun to see, and has surely influenced Kubo's realization of her true feelings in some way.
All in all, this manga is a must read if you're enjoy these sort of romcoms, it's pretty much a constant stream of insulin.
