I am not habitually late, but I have been late before, unintentionally. I do have a bit different sense of time on the whole, and tend to be fairly open-ended about arrival when given the option, but I try to make people aware of it in advance if I'm not going to be somewhere exactly at the planned time.
LOL!--My oldest sister used to arrive hours late for things like family gatherings. We used to wait for her before letting the little ones open packages on Christmas morning at my parents' house... But we finally wised up. We joked that we were going to tell her Christmas was the 22nd just so she would arrive on time Christmas morning.
My daughter is usually late with informal social engagements, and I don't find out in advance, so that sometimes drives me a little nuts. She really is punctual in other areas of her life. I wonder if she just feels like scheduling isn't such a big deal when it's an informal "visit". Who knows?--
Also, it's interesting that "on time" interpretation can be quite a cultural thing. Our friends from Venezuela are a good example. In their cultural view, dinner at 7pm means arrive sometime after 7pm to visit and enjoy each others' company, and we'll sit down to dinner after that social piece is done...whenever that might be. I have learned to understand this about them. We get to visit so rarely, and I know they don't mean anything by it--it's simply their custom, and I don't think they could eat a bite without that social time beforehand :) !