Don't get me wrong, I eat shrimp, crab and lobster all the time, it's just hard to view it as a sacrifice. Same with sushi. Now, canned tuna fish is something that I will not eat under any conditions ever.
I understand. For me, part of the sacrifice is that I have to plan for every Friday all year, which is a day when our friends, acquaintances and business associates often get together. I can't just show up anywhere and be assured that I will have many choices. At the same time, I don't want to draw any attention to myself.
I love tuna salad, but I eat it most Fridays for lunch. There are times that I will eat nothing rather than gag down another mouthful of it. Sometimes I skip breakfast, too. Is that a sacrifice? Not eating something that makes me nauseous? I don't know. :)
Imho, the interpretation of sacrifice may be bit complicated.