not sure about the culture but it’s important to me. not being punctual is depleting someone else’s finite time they have on this planet 

 I agree i just arrived very early Somewhere and it made me think how the Dutch are super puncutual and expect you to be too.

But South America as example is much more loose  

 Less important than spelling.  

 Is it because of culture? I don't think so... 
I've heard if you're always late, it is because of your own selfishness. 
But I always hear that being late is late, being on time is late, and being 15 mins early is on time.  

 important. 

but... many people ignore it, waste people's time and then do it again the next time. when I was in the work force, it was always the same people at work who were chronically late and never learning. 

 I should add but that doesn't include outdoor who occasionally have an emergency etc that causes lateness. 

 It varies based on occasion and others ranging from very important to very low importance 😂 

 If not on time... no friend of mine.  

 Quite. Sign of civility, maturity, and respect.