Is it that awful to be a few minutes early for work consistently? I always think (especially when I’m running late) that budgeting a half hour for unexpected delays would add immeasurably to my peace of mind.
I tell myself that marking students late for class consistently helps to train them for workplace promptness. When an “A” student gets a B because he or she was consistently late, it’s my way of reinforcing the fact on them that employers will regard promptness as the employee’s responsibility. Employers don’t care about WHY you were late just this one time–they want you there on time, all the time, no excuses, no questions asked, no "B-b-b-b-but THIS time, what happened was…"es.
Showing up is important. Showing up on time is important. Showing up on time consistently is important. Showing up up on time consistently without being told how to accomplish this is important.
Explanations are unimportant.