insecure child trauma of guilt from 10 years ago (for Fuuya to use a paperbag to hide his face) where he said "I hate everyone." in a emotional outburst from Umi's leaving (to move out) which upset Umi who told him "I never want to see your face again." ... is ridiculous.
To be fair, it is a comedy, but overall it's mediocre for how immature the main characters are with Fuuya being a creative weirdo hiding his identity while still loving her since he was a child, to Umi slowly (poorly developed from the plots and bad writing) falling in love with him.
In the end he reconciles with her after he rejected her confession from guilt of the past as the climax to a dramatic final plot to then have them become a couple which was very basic and unoriginal.