Vegetarianism is something that I could never do. Abstaining from eating meat would just ruin my life haha.
I could take meat or leave it. I eat vegetarian when I feel like it. 
I could probably abstain from eating some seafood, but red meat and poultry? No way.
I'd agree with that. I don't really like seafood much. Unless it's lobster, I do like lobster. 
I quite like scallops and shrimp. On another note, vegetarians are that way for many different reasons.
That's true. I guess when I eat "vegetarian" it's because I'm not a fan of the taste or texture. It's less about the ethics. 
I can see that, though some people do it for health reasons and environmental reasons too.
Oh sure. I actually raise my own poultry and do all my own butchering so I can be okay with all of those things - the health aspects, environmental impact, and quality of life of the animal.
aesthetic, economic, or personal preference. There are variations of the diet as well: an ovo-lacto vegetarian diet includes both eggs and dairy products, an ovo-vegetarian diet includes eggs but not dairy products, and a lacto-vegetarian diet includes dairy products but not eggs. A strict vegetarian diet – referred to as "vegan" – excludes all animal products, including eggs and dairy. Avoidance of animal products may require dietary supplements to prevent deficiencies such as vitamin B12 deficiency, which leads to pernicious anemia.
. According to the Christian Vegetarian Association, Paul was not referring to vegetarianism, which was not an issue in those times, but to the practice of not eating meat from the meat market because of fear that (like the above issue involving Daniel) it were sacrificed to an idol. "Wherefore, if meat ["brōma", Strong's #1033, 'anything used as food'] make my brother to offend, I will eat no flesh while the world standeth, lest I make my brother to offend