I've had much the same experience. Most have been polite, although that doesn't mean I appreciate them or am contented with their visits. Some, though, have been just... absolutely horrid.
There was one group that painted a cross on my front door. My neighbor told me she almost called the police, she thought Christians had murdered me or something.
Our local Churches don't do any of these sorts of things. They know better, I suppose. I remember seeing in the news that a German missionary had been shot at near Travnik, and they interviewed the father of the family - he was hilarious. I forget his exact words, but in English slang it would be more or less:
"I came downstairs and my little girl was at the door talking to two of those Jesus freaks in fancy suits. So I got my gun, came out, shot once in the air to scare them off. They put up their hands and made a cross in the air at us, so I shot at them."
I couldn't stop laughing. Those kind have almost driven me to the same thing.