Why is Christ's death considered a sacrifice?

[Welsh cake]

Well Robie if you don't like the price paid for you, and it is certainly your choice.
You can pay it yourself.

How can you sensibly do that if someone just paid the price for you.

I may not have wanted my manager to buy me a drink, but I cannot undo the transaction once its done, now can I?

Have a nuclear war, manufacturer killer cyborgs, build a time machine and then terminate Jesus?

Unless of course, you're arguing from a slippery slope that he didn't die for everyone's sins.