Well, without having read the 'naegi's really bad day novel', it could be that Naegi faces personal disasters, like relationship problems, maybe trouble at work or school. It could also involve some external factors that make his day truly awful, such as getting into accidents or facing some form of social embarrassment.
I don't know who the author of 'naegi's really bad day novel' is. There isn't enough information provided to determine that.
A really bad day story might include having a flat tire on your way to an interview. You're already nervous and then this happens. You try to call for help but your phone battery is dead. So you end up missing the interview. Then when you finally get home, you find that your dog has made a mess all over the house. It's just one disaster after another.
Well, without having read the 'bad day on the midway novel', I can only guess. It could be centered around a character who has a really tough day at a midway. This could involve things like financial troubles if they are running a booth, or personal dramas that unfold while surrounded by the chaos and excitement of the midway environment. Maybe there's a conflict between different groups of people at the midway, like the carnival workers and the local residents. The midway is often a place full of energy and different types of people, so there are many possibilities for a 'bad day' story.
A 'brainwashed naegi fanfic' is likely a fan - created story. In it, Naegi might be brainwashed by an antagonist or some sort of external force. This could lead to all sorts of plot developments. For example, his friends might not recognize him at first. Or he could be used to carry out evil deeds against his will. The fanfic could then focus on the journey of either reversing the brainwashing or dealing with the consequences of his actions while under the influence of the brainwashing.
One common element is unexpected events. Like suddenly getting sick or having some equipment break, like your car or a necessary tool for work or study. Another is bad timing. For example, when you're already running late and then something else goes wrong, like traffic being extra bad. Also, things not going as planned. Just like when you plan a nice outdoor event and the weather turns bad.
It could be the common struggles and frustrations that people face at work. Maybe it shows things like difficult bosses, impossible deadlines, or coworker conflicts that many can relate to.
One possible theme could be hope. If Naegi has his best day, it might be because he holds onto hope throughout the day's events.
Well, once I woke up late and missed my bus. Then I realized I had left my wallet at home. So I had to walk to work in the rain. When I finally got there, I found out I had an important meeting that I was completely unprepared for. It was a total nightmare.
I'm not sure specifically which 'naegi best day short story' you are referring to. There could be many stories with a character named Naegi having a great day. It might be from a particular anime, manga or some other fictional work. Without more context, it's hard to say more.
I'm not sure specifically as I haven't read it. But it might be about a character named Conker having another day full of misfortunes, like getting into trouble with friends or facing unexpected challenges in his daily life.