When I was 19, I was a bright-eyed, bushy-tailed young mormon missionary. On my first day out in the field, I was assigned to an area where I lived in an apartment with 3 other missionaries. After I did a little unpacking, they told me they'd agreed to go help someone move a washer and dryer.

On our way there, a group of 16-20 year old kids numbering about a dozen comes pouring out of a duplex. Several of them pull knives, and an argument breaks out between these other three missionaries and these kids. I start laughing, because this is such an obvious attempt to screw with me. Obviously they organized this before hand to freak me out!

And I believed that for the next minute or two, until it became increasingly obvious this was quite real, and things could go bad quickly.

Things escalated until one of the missionaries was able to calm things down and extract us from the situation. I still have no idea why either group was so upset with the other, but I felt pretty sheepish about laughing in the face of people threatening me with knives because I thought it was a joke.