I already read the novel and now I understand why do I feel hole or something missing when...

I already read the novel and now I understand why do I feel hole or something missing when I read the manhwa for the first time, the manhwa cut some part of the novel story maybe a lot of it bcs they cut off part of hyoseop past and building some plots, but I understand they need to cut some part bcs how much chapther it would make but it's still disappointing me