That is the truth. I deal with those in a nice way, though. I invite them inside and ask them if they've ever considered converting to The Church Of Satan, turn on the stereo with Black Sabbath playing, and ask them if they'd like some kool-aid...
The whole process usually takes about 4 minutes, tops, and they bail.
Hey, thanks for the tip! I'm generally a very nice person to people I meet, so sometimes have a problem shaking them -- especially since they're so damn sincere and polite!