Why is the day of Jesus' death called Good Friday?

We're all familiar with acronym T.G.I.F., but there's only one Friday on the calendar that's earned the distinction of being called 'Good Friday'.

It was a bad Friday for Jesus, since He suffered unbearable pain and anguish on that day. But it was a good Friday for us, since all of our sins were atoned for by His suffering and death.

On Good Friday He hung suspended on the cross for 6 hours, including those dark afternoon hours. About 3:00 PM Jesus said in loud voice, "It is finished!" (John 19:30). Shortly thereafter "He bowed his head and gave up his spirit". He died.
"It is finished!" is the guarantee of the peace of mind that we can have in knowing that our sins are fully paid for and we are thus reconciled to God. "It is finished!" is His assurance to us that the way has been cleared for us to someday enter eternal life in heaven.

That's why this is a Good Friday for us and why we take great comfort in Jesus' words, "It is finished!"

Happy Good Friday :)