If you are late without a warning you are disrespectful even before you get there. For you are basically saying you’re time is more valuable then the person you are supposed to see/speak to and with so many means to communicate (texting, emails, voice mail) today there really is no good excuse. It’s just as easy to come a few minutes early then to be there a few minutes late but if you’re just thinking about you’re own schedule then you’re not thinking about me. It’s simple respect my time and I’ll respect yours even if you’re running a few minutes late.