[aflag]

> No it isn't? You don't convert anything, you just do things at the times the locals do them. It's really not hard.

Before you get used to it, when you see a time you'll have no idea what time of the day it is. Is it early? Is it late? Is it during lunch time? You need to convert in your head "11am here means midnight where I come from, so that's actually really late". Very easy to forget and make a mistake.

> No changing clocks, no scheduling a meeting at the wrong time because you mixed up the timezones, no calling your parents and accidentally waking them up because it's the middle of the night for them.

huh? How is using a single time going to help with waking something up because it's the middle of the night for them? I'd say it's more likely. If someone is 6 hours behind you, you'll need to keep in mind that their 10am means what would be your 2am. Even though you both call it 10am, you would definitely not want to call them at 10am. If anything, that's more error prone and confusing.

[lmm]

> Before you get used to it, when you see a time you'll have no idea what time of the day it is. Is it early? Is it late? Is it during lunch time?

That's not a real problem, IME. If someone invites you for lunch, it's going to be at lunch time. If someone wants to schedule a meeting, you have to check your calendar anyway.

> You need to convert in your head "11am here means midnight where I come from, so that's actually really late".

No, you don't. Converting in your head is the wrong approach just as it is for languages. Just get used to when you're going to bed and getting up. (And don't use AM/PM - why would you ever do that? Even within a single timezone it only causes confusion)

> How is using a single time going to help with waking something up because it's the middle of the night for them?

Because you never have to add or subtract a time, which is where most mistakes happen.

> If someone is 6 hours behind you, you'll need to keep in mind that their 10am means what would be your 2am. Even though you both call it 10am, you would definitely not want to call them at 10am.

Right, so you need to know when they go to sleep and when they get up, and not call them when they're asleep. But there's no arithmetic to get wrong, there's no risk of adding six hours instead of subtracting six hours or vice versa.