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!

Why did Santa's elves go to the North Pole's IT department?

They needed to update their sleigh-ware

Why did Santa hire a new team for quality control at the North Pole?

He wanted to make sure every gift was present-able.