Imagine you're playing in the hot sun, running around a lot, and you get super thirsty. Then someone shows up with a big glass of ice-cold water. So good, right? You can even feel your body cool down and your energy come back.
The Bible says Christmas was exactly like that! People were sad and tired, "thirsty" for love and for God. Then, from Heaven (a very distant land), God sent a love letter: He sent Jesus! When the angels announced: "The Savior is born!", it was as if the whole world took a sip of fresh water. Everyone was happy again!