Depending on the project and the needs of things such as; smoothing special FX, grading, CGI, audio and general management etc it is indeed VERY time consuming. Editing can actually take much longer than production (filming) itself.
However, it varies between dull and exciting, again depends on the project. I work from home mostly so if it's a dull project I can do other things to entertain myself.
Yet some projects that I put together that slowly takes shape and tells a good story is very satisfying. It's why I enjoy editing so much. I love to create and visual media is one of my favourite forms of art. Helping directors/writers etc tell a story (be it fantasy, drama, documentary etc) makes my job worth it. I always do my best to edit according to the director/writers wishes as it's their story/vision being told, but I do force certain 'edits/cuts' if I must as is expected of me. Overall, a finished project is always great to see (and sometimes a proud moment).
Now as for Yoohyeon, she did a job well done for her Vlog lol.