It might be time to change my ways. I'm chronically late to important things and I use my niece's battle with leukemia as an excuse.
So being on time is that hard for you huh? Why are you constantly late?
The way I see it, time is relative and it's a non-linear concept. I think time is cyclical, so I get places when I can.
But other people are still expecting you at a certain time, no matter how you feel about the concept.  Sometimes it can be hard to be punctual but it's wrong to lie about the reason you are late. Instead of lying you should just apologize and try to be earlier next time.
They won't understand my time issue though.
At least be considerate enough to show up when they are expecting you, rather than giving false excuses.  If you want, then you can explain your theories about the nature of time, but they do not excuse tardiness.