So you still need lookup table to figure out whether you're being considerate of them or not. At least you don't have to worry also that you're miscommunicating

So you still need lookup table to figure out whether you're being considerate of them or not. At least you don't have to worry also that you're miscommunicating with them regarding when you want to meet! My sense is that more of the problems we have result from not understanding what time somebody is proposing. People are free to point out, after all, that that isn't a convenient time so long as they understand what is proposed accurately. There's some possibility, in fact, that everybody living with their own local time makes it harder for people to learn how their local time works relative to others'. If we all used one universal time, we'd probably have developed an intuition for when people were sleeping in different parts of the world according to that universal time. As it is, we tend to rely on the lookup tables every time.