Mary was a young girl, getting ready to be married. I can remember how excited my wife was when it came to planning our wedding. She spent hours looking at bridal magazines, going over all of the wedding related stuff. It was her favorite topic. I can imagine it was the same for Mary. She was probably thrilled over what was about to go on. Then, the angel shows up and delivers the news. BOOM! All of her plans and dreams, gone. In an instant. This was not good news.
Joseph was getting the final preparations ready for his wedding as well. I am sure he was just as excited, but, as a dude, he had to keep it under control. Then he gets word that Mary is pregnant. He knows he isn't responsible, so it has to be another man. Under Jewish law, he could have Mary executed. He didn't really believe that story she was telling about it being God's Son, did he? Then the angel arrived and confirmed it for him. This was not good news.
There were looks. There were whispers. They lost many friends. Joseph probably lost business because of this. But they continued on. They stayed together and Joseph protected Mary. He married her to protect what was left of her reputation. It was not an easy life.
The news from the angel was not good news. But it became good news. The baby that was born to Mary was Jesus, God in the flesh. He grew up sinless and died on the cross for our sins, the sins that separated us from God and kept from having a relationship with Him. He was bruised and crushed for our iniquities. God turned His back to Jesus in the hour He needed the Father the most. He was buried and, three days later, Jesus made an open mockery of sin and death by coming back to life. Jesus did all of this willingly and He extends the salvation from sin freely to those who believe, without any preconditions or requirements.
And that is how the horrible news became the best news ever.