system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How the time zones where established and why the lines are not more parallel?

Looking at a timezone map the outlines seem to be all over the place, some spots are thinner that other  spots in the same time zone and some times zones are much wider than other time zones.
gpt
Remember that time zones is a necessary evil of having long-distance communication and travel. Until this was a thing, people really didn't give two wits about times in other places. When the sun came up was dawn, when it was overhead it was noon, when it set it was dusk. The end. Yeah, some hoity toity's wanted to know the *exact* time, so we have watches and clocks and stuff, but, again, setting it was easy. When the sun was straight up. You looked at the clock. If the clock didn't say the right time, you fixed it. Time outside the town? Who cares.

But, long-distance travel and communication became a thing, so sorting out time became a requirement. You needed to know when, locally, a train would arrive across the country or continent. You needed to know when you could communicate with someone across the globe. But, given the previous paragraph, you needed to do this in a way that really didn't upset local people, otherwise it would never gain acceptance.

The first decision is the minimal unit of measurement. Time passes gradually across the surface of the Earth, yet you're not going to have thousands of different second-long time zones. An hour is nice and neat. Not too long as to be useless, was already the standard division of the day, and long enough as to not really impact people's lives.

The second decision is where to draw the lines. Ideally, you'd just divide the Earth into 24 equally-spaced sections, each representing an hour. The problem is creates significant impact.

What if a line runs right through a town? You have to change your watch every time you cross the street? Remember, at the time of adoption, most people don't care about this so you want to set it up in a way that doesn't impact them.

The end result is you *try* to draw lines across existing political boundaries. They already exist, so are good reference points. Crossing over one is already a somewhat notable thing to do, since it can result in entering an area with new laws and new customs, so adding "new time" to that isn't that big of a deal. And most of the people who don't care about this don't care about it because they don't communicate or travel outside their town, let alone their county, state, or country, so it doesn't affect them.

The lines then follow these kinds of political boundaries. The problem is you end up with larger than required time zones, meaning you need to pick up the slack somewhere so you can fit them all in. Thankfully we have large swaths of areas with no political boundaries: the ocean. This is also why the most impactful time zone boundary - the international date line - is in the ocean and deliberately carves around any countries that would be in the way.

The last issue is the fact that there is no global entity creating or enforcing these. It's basically left up to local governments, so they are going to carve up their own country how they see fit. So you end up with half-our timezones and large countries - like China - that stuck with only one.