What does it mean always to meet someone on the door?

I think that it probably doesn't mean anything, but either way just always be aware of what is going. If something bothers you more than it usually would, perhaps it's intuition telling you something. Make sure you always keep your eyes open and that you're always listening. To be on the safe side, ask where your dad is going (if it doesn't offed him). That way you know where he is in case of emergency.