When people are nice and friendly, I'm also nice and friendly. When I lived in Ohio, the Jehovah's were the heavy-handed fire-and-brimstone sort. In Canada, they're very Canadian :) Polite, nice, friendly, not pushy at all. So I nod and smile and tell them politely: "I'm an atheist." and they, very concerned and still friendly, "What does that mean?"
"It means I do not believe there is a god. I do not believe Jesus was the son of a god."
So the next time they stop and leave not a pamphlet but a whole book titled "Is there a God" or some such and they don't stay or talk, just leave the book in my hand and leave.
Next time they ask if I've thought about it and read the book. Have to admit, I really didn't read the book, just glanced through to confirm my suspicion of circular arguments and absurdities. Like: "Gravity! Newton didn't MAKE gravity! God did! Gravity is proof of God's existence." That one made me laugh out loud all the way to the recycle bin. So I told them that I've spent YEARS thinking about this and the ONLY thing that makes sense is that MAN made God in MAN's image and then crafted a lot of stories and rules that served a few men, but not all of mankind. Well, the woman looked like I sprouted horns in front of her and the man just looked confused. Left ANOTHER pamphlet and left. (I take all pamphlets they give and promptly recycle them. My theory is the more I have the fewer will land in the hands of vulnerable people.)
I strongly suspect this man and his wife say to each other, "She's far too nice to be an atheist" as they leave my driveway. I suspect they are misinterpreting my politeness for a weakness or an interest in their religion.
There is not the slightest chance they will ever convert me.
I'm not uncomfortable by their presence and I think I'm doing the world a service by recycling their propaganda. But...what can you say to a Jehovah's witness to get them to realize it won't gonna work? I've been blatantly honest and that's still not doing the trick.