By that I mean you had an encounter with someone that pushed their crazy theist beliefs to you without provocation.
I broke their faith.
When you change addresses it seems that all the local churches get a heads up about you being "new" to the area. So I wasn't necessarily surprised to see missionaries pop by every so often to spread the "good news."
At first I didn't care, they arrived like clockwork each week so I seldom overslept and they were usually non-confrontational about it, readily accepting my polite refusals: told the Catholics I was excommunicated, offered the Mormons a cup of coffee, explained to the Witnesses that giving blood saves lives, etc. Except for this one guy... I don't remember what faith he was selling but he wouldn't take "no" for an answer and kept coming around week after week for about a month (once he even stuck his foot into my home as I tried to close the door). So I invited him in.
He sat on my couch, I offered him food/drink, and I asked if he accepted the bible as "truth." He gave me a firm "Yes!" and something about how the "bible is truth" etc, so I asked him for his bible to skim through, he readily handed it over. I then flipped to some "random" passages (I had previously memorized the selected verse locations thanks to my Skeptic's Annotated Bible), asked him if he agreed with X, and whenever he said anything resembling "no" I read the corresponding verse from his bible.
"Do you think it's ok to murder children? It happens in Exodus"
"Why would God kill an innocent child? He does so in Genesis"
"How do you feel about the raping of girls? Read up on 2nd Peter."
"Did you know divorce is a sin? No, really, it's in Leviticus."
The guy lasted about 10 minutes before tears started to form. I asked him how many times I had politely declined, how many times did you ignore my polite requests? When the crying stopped I gave him back his bible, handed him a bottle of water, and sent him on his way.
Saw him last year at a bar, he bought me a beer and thanked me for showing him "the truth."
When Obama won the first time, my neighbor drove past me as I was taking out trash. In 12 years I have hardly spoken with him, just an occasional wave. We live in a semi-rural area. He stopped and asked me what I thought about the election. I told him that I was happy about it. He said, "Well, all I can say is that I hope Jesus comes soon." He had no idea of my beliefs or lack thereof, but had no problem pushing his crap on me.