Luke seems to be where the Christmas story I learnt in school comes from, we have the Most Ridiculous Census Ever (seriously, you do not make everyone travel back to their home town 90 miles away to register for a census!), and Mary has to put her new baby in a manger because there is no place left in this little village with all the people who'd been born there and moved away popping home for the census.
Also some shepherds abandon their sheep after a vast heavenly army of angels appeared and told them about the baby. We don't normally get taught about Mary and Joseph sacrificing birds when they presented Jesus at the temple.
So, if you were Simeon and you'd been told that you wouldn't die until you'd seen Christ, would you go and seek out an audience with Jesus or avoid all contact and hope to live forever?
The 12 year old Jesus stays behind to chat to the teachers in the temple court, worrying his parents but amazing everyone else with his understanding.
John the Baptist is paving the way for Jesus with his preaching, though it gets him in trouble with Herod and he is imprisoned.
And then Luke lists Jesus' lineage through Joseph who isn't his father (and apparently there are several differences between this one that the one in Matthew).