Some […] core principles that we were all (generally) taught are to be on time and to stick to what you promise or commit to. […] And, we are told to do one thing at a time (“Eine Sache nach der anderen!”) and “alles zu seiner Zeit” (all in good time). And, for us, it is “normal” to be on time.
People who tend to be late are “abnormal,” and based on a very common understanding, need to be admonished or avoided. Having understood that, it might not come as a surprise to you that Germany ranks as one of the top countries worldwide when it comes to the stress we put on punctuality (“Pünktlichkeit”).

In business, arriving even a few minutes late (without a very good excuse) will create a bad impression. If you think a “Sorry, I was held up at another meeting!” is a very good excuse, forget it! Also, telling me that when coming from the airport during rush hour, it had unfortunately taken you more than the anticipated 10 minutes to arrive in the city center won’t make things better.
Normally, in business, I would expect you to arrive at my office some five to 10 minutes before the fixed timing (and ask my assistant to let you wait until the clock strikes whatever hour we have agreed upon). On the other hand, at a trade show, while people would expect you to show up at 10:00 a.m. sharp, for example, a delay of five minutes would usually not be frowned upon. However, if you are running more than five minutes late, better give your appointment a call and inform him or her of where you are and confirm that you are on your way. Maybe they will offer to reschedule or try to meet you halfway.
“After coming back from a long business trip to India, where things might not go as you want or not always as planned,” a German gentleman recently told me, “I was waiting for a train in Germany. It was fascinating to see how a delay of two or three minutes made everyone completely nervous, or even anxious, that they might run late for something.” He continued saying “the reactions were also very interesting, as many became angry within these few minutes and started complaining. First world problems, I’d say.”