Luke 2:15 NASB
When the angels had gone away from them into heaven, the shepherds began saying to one another, “Let us go straight to Bethlehem then, and see this thing G4487 that has happened which the Lord has made known to us.”
The Greek word translated as "thing" is "Rhema" and has several meanings, one of which is the "thing spoken of."
So the idea is not any old "thing" but whatever event was verbally described.
Therefore, if the translations more closely adheres to the historical-grammatical meaning of this context, it would read, "...and see this declared event that has happened, which the Lord has made known to us."
The problem with translating a contextually indicated object or event as "thing" is that anything can be read into the text.
For example, most believers take for granted that "All things are possible with God." But what scripture actually says is "all of the contextually indicated things" are possible with God." And what is literally said is All (ellipsis) are possible with God. The word "things" again has been supplied by the translators. Matthew 19:26 and Mark 10:27 should be contextually translated as All salvations are possible with God.
Another verse in the same vein is Luke 18:27. The NASB adds to the text "the things that are impossible with people" when the actual text reads "the impossible with people" are possible with God.
Sadly, the Greek word for "all" (pas) is translated about 170 times as "all things." A simple fix is when we come across the phrase, is to consider it as if it read "all these things."