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. 
That's really cool! There are even more reasons than that, like aesthetic, economic, and personal preference like yourself.
Wow, there are lots of reasons that people become vegetarians!