I guess I'll be the party pooper. I really don't give EXCUSES...
Anyway, for work: I usually go in early, so if I'm late, it's legit. When I'm late, it's usually on a day that I decide to go in ON TIME (which, if I'm there right at the beginning of my shift, I tend to feel guilty) and there's an accident or something that causes heavy traffic. Anyway, because I usually go in about an hour or two early on the other days, I don't feel so bad. In personal situations: I just say "I'm running a little late" and leave it at that.