Math Memes

Try 24-hour time for a month. It's slightly weird at first solely because 1) everyone else uses 12-hour and 2) you've used 12-hour your whole life, but after that it's great and frankly better than what you use now. Translations between 12-hour time become 100% automatic, so you can use it in your personal life without feeling like you're switching (you might even get one or two friends to join you). The following are advantages just for you, not accounting for the larger advantages that come when everyone is using it:

• You can drop the AM and PM on digital clocks with no loss of information. It's a small thing, but this gives me room for a seconds position on the clock on my taskbar. (Side note: given 8 billion people on Earth and given how often time shows up, I feel like these trillions of miniscule savings getting rid of AM and PM might add up to something actually meaningful.)
• You'll never have that experience where you oversleep during a nap so badly that you get confused if it's AM or PM.
• Most intervals we usually talk about for things (e.g. "I have school from 6:00 AM to 2:00 PM" or "I have work from 9:00 AM to 5:00 PM.") do not include midnight in their range (e.g. "I slept from 9:00 PM until 6:30 AM"). Thus, arithmetic is easier because you don't have to account for the modulus (at worst in the latter example, it's the same). For example, when I go to school from 06:00 to 14:00, that's just 8 hours. When I work a 09:00 to 17:00, that's 8 hours. It's just the actual arithmetic. It's currently 10:00 and the assignment is due at midnight? Then I have 14 hours left to get it done. Whereas for 12-hour time, I need to account for the modulus: "okay, there's x hours on this side of the 12 hours and y hours on this other side; add those" is how I probably do it in my head. Subtracting times is especially nice. For example, if something has been happening since 00:30 and it's now 13:45, then I just need to subtract 30 minutes from 45 and I immediately have my answer. 1:45 minus 12:45, meanwhile? Nah. This also makes timezones much easier to do mentally. If I have +14 for my time and it's 06:00, then I know it's 20:00 there. Trivial. You do lose that sweet spot where something is exactly 12 hours apart, but that's miniscule compared to how easy everything else is.
• Starting at 00:00 for midnight instead of 12:00 is just so much nicer. 12-hour time has no 0, which to me is just kind of stupid. Namely for aesthetic, intuition, and arithmetic reasons.
• If speaking to someone internationally, intuitively knowing both formats means you don't even need to think about a conversion (let alone do one at all once you really get it down). Lots of countries use 24-hour time orally and written, and even more use it just in writing.
• Date and time formats use 24-hour rather than 12-hour time, so you can read these automatically instead of needing to convert.
• This one's very unobjective, but I feel like I've been less inclined to go to bed late when dealing with larger numbers. "Oh, it's just nine" versus now the 20s are "late" and when I really need to start thinking about how and when I'm going to bed. Obviously it's possible this is just my monkey brain being weird in a specific way and that nobody else would have this, so pay attention to the other reasons instead.
• (Not beneficial to an individual using it on their own as an adult, but I wanted to bring it up.) It's arguably slightly easier for kids to learn. Kids aren't up at midnight, and so they don't really have to care about the clock rolling over while they're fast asleep (if they do, they get the much more intuitive '0' than '12'). On the other hand, the clock rolling over at noon means you as a kid really do need to understand how that works.

It's just objectively better in most meaningful ways, and like the metric system:

• Its benefits are most evident if you grew up with it and everyone around you uses it.
• Its benefits would still be evident if everyone switched to it but hadn't grown up with it.
• Even if you didn't grow up with it and no one else around you uses it, it can still benefit you to use it.