wishing Facebook friends happy birthday...

It seems I'm in a quandary every time I see that a Facebook friend has a birthday?

Of course some are slam dunks, because they are truly your friends. 

Others are more like acquaintances and depending how I feel that day- I really don't want to bother.  

I don't let people write on my wall, therefore unless they send me a private message or if I happen to post something which opens me up to likes and comments- they can't send me a birthday greeting.  

However, if they are my real friends- they have my cellphone number and can text me or better yet, leave a birthday voice mail.  

Yet I believe everyone enjoys a birthday greeting even if you're just acquaintances with them...