Well "Bless My Heart"

I have a GREAT story to share about a professor here where I work. We really love her, even though she is from Michigan. We are true southern woman and bless her heart, she can't help where her parents reared her now can she??? She has however, done her best to accept our charming southern ways!

In her culture class this summer, she talked about the difference in not only religious cultures, but geographical cultures as well. Explaining to the students that it amazed her that in her first few years of teaching here that on her evaluations she was considered to be rude or mean when she graded papers. She explained to her students that where she came from you did not beat around the bush, you just told it like it is. But she further explained that she had recently learned that if you say "Bless your Heart" after saying something negative, it made it okay. So from now on when she marked papers with comments such as "no depth" or "needs more explanation", etc. she would follow the comment up with "bless your heart" and their feelings would not be hurt.

Of course, this was much funnier coming from her since she gets out 2 words for my 1 word every time ~ 'cause I have a Texas drawl to go along with my GA hick accent.

I was very quick to explain to her that "Bless your heart" could be used both in a true caring manner or just plain snidely ~ depending on the situation!!! So all you sweet southern interwebs, I have a couple of questions for you. I remember reading that if you say, "Bless your heart you worked so hard today" -vs- "You worked so hard today, bless your heart" ~ that it means two different things. Is this true and which means what? Or is it just in the tone of voice?

Also, if you have a good "bless your heart" story, share it!!!

Bless your hearts all of you and I mean that most sincerely!