I grew up in Japan. So my “normal”s are based on my Japanese background. And I knew there are so many different “normal”s in different countries. And I usually start to “understand” them by experiencing those differences.
One of them is “be on time”.
Japanese people are known as punctual. And it seems correct. Also, sometimes Japanese say non-Japanese people are less punctual. It seems also true that often you might find Japanese people come to a meeting room before anyone else. And usually, it is 5-10 minutes earlier than the meeting time. On the other hand, you might find some non-Japanese people show up at and/or a little after the meeting time (I have seen many non-Japanese people show up a few minutes or earlier than meeting time too).
However, I started to question the idea of “be on time”. Does everyone in the world have the same idea about “be on time? Probably not.
In Japan, we have the phrase “being 5 minutes in advance”. It means you are expected to be at your destination for 5 minutes in advance. For example, if you have an appointment at your client’s office at 1 PM, you will plan to be there at 12:55 PM. You do not aim at getting there at 1, but 12:55. Or if there is a meeting in your office at 10 AM, everyone is expected to be in the room by 9:55 AM. If you have an appointment with your client, it is better not to arrive too early, but if you have a meeting with your colleagues, 10 minutes in advance is OK as well as 3 minutes in advance is acceptable. However, if you walk into the meeting room exactly at 10 AM, others might think you are late.
And I have realized this way of thinking/behavior had cultivated in our minds as early as six years old when people start to go to elementary schools. When a school starts at 8:30 AM, all the students are expected to arrive at school by 8:20-8:25. Some students (especially at a younger age) are happy to arrive there around 8:00 so that they can play before school starts. Once you get to the school, you walk into the building to your own classroom so that you can put your bag away. You might need to do something such as taking your homework assignment out to a designated place to prepare the day, and you are expected to do everything in advance. Then you have some free time until 8:30.
Also, if you arrive at school after 8:30 AM, it is considered as tardiness. Because you should be prepared by 8:30.
I believe it is the same in every school in Japan.
On the other hand, I have sent my children to two elementary schools and one pre-school over the last five years. Also, I’ve asked a couple of Japanese friends who send their children to schools in the USA. So based on my own experience and stories from my friends, students in the US are not able to go into their classrooms until 8:30 AM (if the starting time was 8:30 AM). So if they arrive at school 5-10 minutes early, they have to wait until the doors open. It is not a playtime even if they arrive early. Some of the schools make students wait outdoor (except bad weather days). It means adults need to stay with their children until they walk into the school buildings.
In my own children's school, the school building doors open at 8:30 AM but it usually takes 10-15 minutes to walk to their classrooms and get ready. So the doors stay open until 8:45 AM and arriving before 8:45 are not considered as tardiness.
If that was the case, who would try to go to schools at 8 AM?
It’s only cases of schools, but schools create fundamental ideas in society because it is usually the first social experience for all of us. So you might be able to say that it is natural to think you should be there BEFORE 8:30 in Japan, but it is OK to be there AT or AFTER 8:30 in the USA.
It’s not good or bad. It’s just different.
So do not judge people if he/she is lazy and/or less punctual even if he/she doesn't show up 5 minutes in advance. If you feel you want your colleagues/friends/peers to arrive BEFORE the meeting time, you should make it clear that you would like to start a meeting AT 8:30 so you expect everyone to come into the room a few minutes in advance to prepare the meeting.
To tell your expectations clearly is key for creating a good intercultural communication and interaction.