My own data point:

1. I don't eat any air-breathing animals or cephalopods; I still eat non-cephalopod seafood.
2. I am concerned about animal suffering, environmental impact, food efficiency, and health. (Cost and ease of preparation are also factors.) I can enjoy an excellent quality of life with this restricted diet.
3. I do not eat meat when it's offered to me, and so far have not been hungry enough to eat it for that reason. (If I were stranded on a desert island, I would eat animals.) I sometimes order soup in restaurants without asking what kind of stock it was made with.
4. I hope to have children and would attempt to raise them pescetarians, although I would not object if they wanted to try out meat once or twice after they got old enough to understand the reasons not to.
5. I occasionally make attempts to convince others to cut down on meat consumption, but have met with no success.
6. I eat an assortment of soy products, other legumes, eggs, and dairy to get my protein, and take iron supplements.
7. I have considerable respect for people who are more restrictive than I am, until you get as far as fruitarians and the like who don't seem able to get adequate nutrition. My reasons for being a pescetarian allow that many less restrictive individuals wouldn't be well-served by changing to a diet more like mine, although I do think there isn't enough thought about the possibilities among meat-eaters.
8. I became a pescetarian when I was seventeen, and decided a few months ago to stop eating cephalopods (although I haven't, since that decision, been presented with an opportunity to eat squid or octopus).
9. I was never a big fan of meat in general, although I enjoyed certain dishes. The only meat that still even looks like food to me, much less appealing food, is chicken fingers.
10. I tried to become a vegetarian when I was sixteen, but found that my limited range of tastes and reliance on school cafeteria food had me eating very poorly; this lasted only a few days. My more permanent switch came when I developed a taste for vegetables and started to learn to cook.