Why was Santa's little helper feeling depressed?

Because he had low elf-esteem.

What's the hardest part about celebrating the "Twelve Days of Christmas" in an apartment?

Trying to find enough room for twelve drummers drumming, let alone a partridge in a pear tree!

What did the Christmas tree say to the ornament?

You look great, fir real!

Why are Christmas trees so bad at sewing?

Because they always drop their needles!