I need advice, help me out, 10 points to best advice?

So...my close friends are very rude. They're awesome friends but lack manners. They come to my house. and my parents ALWAYS offer them dinner(and when my mom makes dinner she really makes dinner) The other night..Linguini with clam sauce. Tonight..penne with vodka sauce.After dinner, my friends never ever say thank you. Like i will say thank you to my mom for dinner, but they don't. When i eat over a friends house(which is seldom) i always say thank you. I go out of my way to say thanks to the parents. Or i say "can you please tell you mom i said thank you." That's just how i was raised. and they always leave their messes for me to clean up at 11 at night. and they never fix the couch cushions when they sit on them. I'm tired of it!