Hmm, interesting question. I think the scenes I enjoy writing the most can be boiled down to two types. First is he blandly ironic type where the humor is really understated, so much so that it's the kind that you have to read twice and be like "that is funny...maybe...ok it is funny but I'm not sure why!", that kind of feeling. Haha. The other type I like is the action scenes, like fighting and stuff. It's fun.
Another type of scene I find a challenge to write, but fun as well, are those bittersweet scenes. I hate emo scenes.
I really really try not to overdo the emo when I have to write that kind of scene, so I always intersperse a kind of...しょうがない or "can't be helped" feeling that is both sad yet bittersweet at the same time? Dunno, my sadness tends to mix humor in, just like the way I am in real life. I tend to make fun of myself when I'm incredibly upset, so I do the same to my characters. Haha.
But yeah, I enjoy writing most scenes, it's hard to say what I hate writing per se, but it depends on my mood to see what makes it easier. I also have some difficulty with perv, I keep having to stop at parts, hit my head against the nearest hard surface, then continue again. Lol. Hence I try not to write pervs?
It's bad for my health~