my FAVORITE is when i hold the door for someone and they don't say anything!!?? no thank you! no smile! no head nod! not even a "thanks for holding the door stupid!"........inside i feel like BITING them in the face...instead i just say very loudly "YEA NO PROBLEM AT ALL, YOUR WELCOME!", "DON'T WORRY ABOUT IT!"....hahahaha it makes them even more miserable, plus everyone around looks and gets that i held the door for them and they didn't say thanks.