I always try to be punctual and most often than not I am the one who waits. Still I don't understand people who are waiting others to justify themselves why they are late, or those who try to explain why they were late. It's unnecessary and just takes away further time. Sure I'll tell them to fuck themselves, but we should do what we prepared to do. Even a good explanation, an acceptable excuse won't make it "not happened".

But for example in school, when a student is late giving reasons is even more useless exercise, the teacher won't believe it anyway. So in this case the student can say literally anything.