I've never eaten any shelled sea creatures because I imagined the texture to feel like blowing your nose when you have a cold and sucking everything off the tissue. I don't know, I've eaten raw egg before, but eggs are so transparent and clean looking that I can ignore the gross texture.
I don't eat meat or anything else sourced from animal carcass because a) I feel more at peace that my flesh isn't sustained by something else's death, it just seems nicer, and b) I don't want to support some of the practices in the meat industry. There are a few more, but those are the main ones. According to one of the premises of my vegetarianism, I should be turning down non-fair-trade chocolate, leather, perhaps milk, and all possible factory farm products if I'm offered, but it's just convenient to draw the line at meat because people tend to be more used to vegetarians than people who examine the ethics of the consumption of every specific product and choose accordingly.
Other than that, I can't think of anything in particular that I turn down, although there are things I don't buy and avoid having too much of. I don't really like soft drink/soda much, but I make my own lemonade with actual real lemons and about 1/5th of the sugar.