(I often get confused when people give me good wishes for things they're not having as well. When my colleagues say "have a good weekend" or someone says "happy Christmas", the natural reaction is "thanks, and the same to you". When I take time off work and a colleague says "have a good holiday", I have to almost physically bite my tongue to stop myself reflexively saying "you too", because it takes me a moment to remember that they're not having a holiday at the same time. So it's rather nice to be able to respond to "happy birthday" with "same to you" this once :-)
(I often get confused when people give me good wishes for things they're not having as well. When my colleagues say "have a good weekend" or someone says "happy Christmas", the natural reaction is "thanks, and the same to you". When I take time off work and a colleague says "have a good holiday", I have to almost physically bite my tongue to stop myself reflexively saying "you too", because it takes me a moment to remember that they're not having a holiday at the same time. So it's rather nice to be able to respond to "happy birthday" with "same to you" this once :-)