Language is also a social construct.

So, let’s put it this way. Let’s say you have this nonsensical idea of a unique timezone for the planet. We’ll base it on UTC for simplicity.

You are in new York. It’s 1000. For you in new York, it’s the middle of night. You’ll wake up in a few hours. Your day usually goes about with wake up and work around 1400, lunch around 1800, end of work around 2200, sleep around 600. You can live you life with that. It’s merely a social construct. It’s completely stupid as a construct because it’s not setup for your actual day. The 0 means absolutely nothing. The 12 and the 24 neither. Why have a 24 hours clock for this? But a decimal clock would do nothing more.

Now you need to work with someone in the UK. Can you talk to him right now? Who knows? You need to ask Internet about the time delay between where you live and where he lives. You learn it’s +6. Or -6. Who cares. Now you juggle with 2 times at your work: your usual one, and your colleague one. Congrats, you made a timezone again. When you need to know when he starts work, you do the maths : 1400-600=800. He must starts at 800, unless there’s some cultural differences.

Now what you call 1800 is called 1200 for him. You made the same concept, the lunch time, have a different name depending on where you live, and that is after the translation.

Why even have a time at this point. It’s more confusing than anything. Let’s just have minutes.

You’ll have wakeup +200 for example. At wakeup +400, it’s midday. Midday +400 is the break. Break+400 is dinner. Dinner +400 is sleepy time. Now that would be much more sensible than your unified clock. There would still be problem with timezones interaction.

But there’s nothing to do about timezones. It’s and effect of the spherical earth and general relativity. In physics, there is a clock for each and every position, and a delay between each. Most of the time it doesn’t matter, so you use your local time. But when it does, you do timezones. Because that’s how the world physically works.