Those awful 4 words. "I love your shoes".
Now, w/o cheating [checking other responses before you post] do you KNOW how you would react?
To simplify, let's assume, you don't see who said it, but the voice certainly sounds female and it sounds like they are within 15 or 20 feet away. [Not 100 feet away and shouted for the whole store to hear]
1] Your heart rate would likely instantly jump to 150 beats a minute and you would likely drop and spill your purse and you would do your best Run Forrest Run impression?
2] You would instantly just KNOW you had been busted? Followed by #1 reaction?
3] Immediately counter attack and go on the defensive with a well rehearsed verbal assault?
4] Thank her for the compliment and/or offer to her where you bought them?
5] Simply say "Thank You" but with your body language let her know you are open to questions?
6] Feel the need to explain to her WHY you are "dressed up"
7] Ignore her/Pretend you did not hear her?
8] Other?
Feel free to pick as many as you want!