Transparency - I don’t know a good subject.

Thank you everyone for the replies. Yes, it does seem like as the OP, I left off some obvious other choices for responses.  But basically, I think it was a good exercise for me to see ways others deal with a situation that you don't want to answer to.  I guess I was raised by a mom that feels like she should say yes to most everything.  I'm fairly blunt and will just say that I am not able to make it and sometimes offer the reason.  But that also gets me into trouble sometimes.  I have a friend who I suspect is replying 'yes' to invitations, but then consistently gets 'sick'. It's become so often, that I'm not sure if this is a tactic to avoid replying no, or purely coincidental.