Good thread, I am a guy that was gay as a picknic basket from day one, nobody was too shocked when I came out, but I am also one of the ones that has NO gaydar at all.
I had a coworker in Florida that asked me if I want to hit the Taco Bell for lunch not long after I started there. I knew he lived with a girlfriend and people always went off in groups or other combinations so I thought nothing about it and went. On the way he just out of the blue said he would do ANYTHING sexually. I got so flustered I will not say the dumb thing I responded with, I was pretty floored, but I also reacted defensively. Instinct told me he was trying to get me to admit I was gay because gay people were NOT accepted at that office.
He was doable too, but he never again made anything like such a comment, and even someone like me could tell I was gay, I lived with a guy in Ohio, move to DC with him, then on to Florida, and there was just one gay bar in town on a busy street, someone HAD to have seen my car there, it was unique.
The result is that I have not been with a guy in about 4 years. In fact the last guy I was with is a guy that sort of picked me up in a straight bar in my hometown on new years eve os 2002, it was my sisters very cute boyfriend. He KNEW I was gay because my sister can't quit harping about the REAL blacksheep in the family.