Manners, Have They Fallen By The Wayside?

Maybe it's just me, but I've noticed manners slowly starting to go away with some people. 

I've seen it here and there with total strangers, but most recently noticed this with a friend of mine!  I talked about this on the air with Michael and Larry today and they were kind of surprised that a grown woman in her 30's, was lacking manners so badly.

I can't figure out if she is being ungrateful, which I hate to think because she is my friend, but she never ever says 'please' or 'thank you' for anything!  I thought maybe it was an oversight once or twice, but after a while of doing nice things for her, I started thinking, geez, does she even appreciate it?  I'm not sure!

Most recently, we went to dinner and I paid.  I didn't say I was going to, just when the bill came, I paid for it.  She didn't acknowledge that I paid, nor did she thank me for it.  I didn't do it to be acknowledged or praised, but a simple 'thank you' would have really gone a long way.

Now, I can do either one of two things.  Abruptly stop being polite to this friend of mine, to see how she reacts...but since she's my friend, I don't want to do that!  Or, I can call her out on it.  I'm not even sure she realizes she's doing it, and I don't want to create an awkward situation.  I'm not sure what to do in this situation.  I just want a simple please or thank you!  I don't think that's too much to ask, right?!