Time blindness is one of the most misread ADHD experiences in relationships. From the outside, being late repeatedly looks like disrespect. Like the person's time doesn't matter as much as yours. Like you're saying, without saying it, that you could make the effort and you're choosing not to.
This reading is deeply painful for the person being waited for — and deeply unfair to the person who is late. Because the experience from inside time blindness isn't neglect. It's closer to temporal disorientation. Time doesn't feel the way it feels for other people.
How time blindness works
For most people, time is a continuous, roughly felt thing. You know when an hour has passed. You feel the approach of a deadline. Your sense of "hurry up, you're about to be late" arrives with enough lead time to actually act on it.
With ADHD, the internal clock is unreliable. You're deeply in something and then suddenly 90 minutes have gone without any sense of them passing. Time, for many people with ADHD, exists in two states: right now, and not yet. Not "in 20 minutes." Just: not yet, until suddenly it's past. The arrival is always a surprise.
The impact is real too
Knowing the cause doesn't make the impact of being repeatedly late easier to absorb. The person who was left waiting at the restaurant, or who had to cover for you at the meeting, or who started to feel unimportant — their experience is also real and valid.
The honest position holds both: this is a neurological difference, not deliberate disrespect. And it still causes harm that deserves to be acknowledged, not just explained away.
The conversation that actually helps is usually the one where you stop defending the cause and start talking about the impact — not denying one to focus on the other, but holding both at once.