Instead of condemning the behavior, try to understand what is going on by that person that is making her late.

If it is a one-time deal, just let it go. Don’t use any time thinking about it.

If you are discerning a pattern, try to understand her. Here are some typical reasons why people are late. These are just to give a picture of what might be going on. It just may be that none of these pertain to her.

1. Some people like the attention (whether positive or negative) that they get when they are late.
2. Some people feel like they always need to apologize for something, or they feel guilty about something. So when they are late, they apologize about that, and not necessarily what they really feel they need to apologize about. (deep psychological stuff here)
3. They are indifferent to the impact their being late causes to others. Some levels of egocentricity here. They are caught up in their own needs and fail to see the perspective of others.
4. There are people who don’t want to be there first and then have to hang around and do nothing. So they are consistently 10-15 minutes late. So they do know how to work to be there according to a schedule, just it is their own schedule.

And then there are those whose lateness negatively impacts them too. Like chronically missing the plane, etc. Why are they always late? Seems like they are missing something in the realm of executive functioning. Something about time-management. Or maybe it is priority management.

Let’s turn the question around just a bit. What are people who are always on time doing so that they are on time? What steps do they take so that they aren’t late?

1. They live with the clock.
2. They correctly estimate the amount of prep time (travel time, etc.) and plan backwards about when they have to start.
3. They adjust their plans accordingly – on the fly – so that they can begin the prep (leave on time). They might pause in middle of what they are doing Or step up the pace,. Or leave out some details. And they keep checking the clock. And keep adjusting.

So those who are chronically late, may not be doing these steps. They may be losing themselves in what they are doing and don’t notice the clock. And they won’t (or can’t) stop themselves from that work. And then they are late. It’s a self-discipline issue.

And of course, there are those issues of crowded schedules. Morning rush. Bosses who just won’t let employees out on time. Not talking about those here.

To understand the person, look for patterns: Does this person have issues with self-discipline in other areas as well (can’t say ‘no’ to junkfood or partying all night)? Is this person somewhat egocentric in other areas?

Of course, it might be something not mentioned here at all. This was just a quick short thought about why some people are late way more often than others.

Understanding the underlying issue might help you determine the way you should respond to this person’s lateness.