Things I don't understand about the workplace

Disclaimer: All of the following may come off as highly sarcastic. It is not. My questions are not rhetoric questions. If you have answers, please comment and let me know. You will be doing me a favor. Really, I mean it. 

1. Formal Clothing

There are a number of social norms in the workplace that I don't understand. I can't help but wonder where these norms originated from.

Formal clothing for example. Why do people need to wear suits and ties to office? I don't see why you can't wear casuals to work and dress up for meetings with external clients. Whenever I dress up for anything, a lot of my attention and energy is on my clothes. I actually find myself working best when I'm in my most comfortable clothes which require least attention.

2. Casual Fridays

Another related thing I don't understand is casual fridays. Apart from the fact that there is only one day of the week allocated to casual wear, why is it friday? Friday is probably the happiest day of the week anyway. If anything, wouldn't it make sense to wear casuals on Mondays to ease the blues of starting a new week after the weekend?

3. Separate Offices

Apart from clothes, I wonder why executives have separate offices. Do they need more silence or privacy to do their work than other people in the company? Or do they have more private meetings? Separate rooms for executives often just increase the distance and hierarchy among employees and I can't understand why there can't be separate meeting rooms or private rooms, kind of like libraries in colleges, which can be used by anyone in need.

4. Fixed timings

The 9-5 timing is also a strange phenomenon to me. Different people have different times at which they are most productive. So why force them to work between 9-5? Why not just let decide on their own work timings? Maybe meetings which require everyone to be physically present at office could be between a designated time (like 9-5), but apart from that, as long as people do their work on time, I don't see why they need to work in specified hours.

5. Fixed Workplace

Infact, if you really think about it, a lot of jobs today shouldn't require people to show up at office at all. They can just work from wherever they are. It would save a lot of commute time and money. They could go to work if they want, but unless they need to work with a team or attend meetings, they don't need to show up at a specified location everyday.