When you are the host/ess it is extremely impolite, downright rude as a matter of fact, not to profusely offer whatever it is you’re serving. They will say no (see next little bit) but you must continuously insist that they have a little, even going to the extremes that you will be personally insulted and disappointed if they don’t. Swearing by God’s name that they take some is also acceptable ( even expected?) if they refuse. This shows them that they are appreciated, loved, etc.
Likewise it is extremely rude to accept whatever is being served without a few protests (see cultural observation I about being ‘full’). You must insist that “You couldn’t possibly!” “You’ve just eaten!” or “Really there’s no need to go through all the trouble!!”
Two scenarios that illustrate my point:
A good friend had a potential MIL over. She, being raised in a somewhat ‘westernized’ household, hadn’t been taught the proper etiquette of dealing with potentials and her mom wasn’t there to guide her. She came in with the coffee and asked if they wanted. They, obviously, replied that she shouldn’t have gone through the trouble! and they couldn’t possibly have any! So she turned around and took the tray to the kitchen. Untouched. They verbally raped her when the left. Her reputation suffered horrendously.
Me. Our foreman was over, back when we were renovating our house, and I was serving something. I asked him if he wanted. He said no. So I went on to the next person. He’s like “Hold on! Get back here! I forgot your Canadian.” And he takes some. LOL. Needless to say, none of the other men present refused anything from that day on.