When you wish someone "many happy returns of the day", it is literal. It is an archaic-sounding way of saying "live long and prosper", and a bit more personal.

I hate it when sincere phrases get turned into "sayings", that people mouth, but they don't mean, like "how are you?"

I've heard people say that to be polite, you are not supposed to answer that question. Which to me seems like saying, "well, I'm going to ask you how you are doing, but I'm really not interested in the answer, because I was just saying that so you'd think I was polite"... Grrrrrr!

When I ask someone how they're doing, I want to know! If I don't wanna know, or if I don't have time to listen, I just say "Hi!" and leave it at that. (Or: "Hi! I'm in a hurry, bye!")

Anyway, HAPPY BIRTHDAY LEEJ! And many happy returns of the day.