when I first read this webtoon, I imagined the conflict for the first couple is like....
sunbae still trying to make haemin to show his attention more. Haemin thought sunbae didn't like him. An then haemin found someone pretty and took pictures of that person. Sunbae looked into Haemin's camera and was anxious that haemin will stop liking him. Sunbae decided to be more aggressive.
I feel like the author just brush off about haemin's desire towards pretty things.