Are you also incapable of telling people that you won't be on time? You seem to articulate it fine here.
If you tell me that you'll pick me up at 5pm, but show up at 7pm... I'll be upset most likely. But if you tell me that you'll pick me up at 5pm, but will probably be late, maybe even hours late... I'll get it... And will adjust accordingly (most likely I'll get a ride with someone else if at all time critical).
Whatever time estimate I give you, I will usually be later than that. Telling you I might be hours late for a 5pm meeting will probably end in me arriving at 9pm.
That's why I find it best to have a reasonable time to aim for, and the people that know me know they will need to be able to accommodate my late arrival. And every once in a while, I might even be on time, though I do consider "5 minutes late" as "on time".
Yes, the people that know me are nice and patient people. That's probably a major reason why I know them in the first place.
If you tell me that you'll pick me up at 5pm, but show up at 7pm... I'll be upset most likely. But if you tell me that you'll pick me up at 5pm, but will probably be late, maybe even hours late... I'll get it... And will adjust accordingly (most likely I'll get a ride with someone else if at all time critical).