What do you call a reindeer with bad manners?

Deer-respectful

Why did the Christmas tree go to the barber?

It heard it was time to get a good trim and 'Deck the Halls!'

What do you call a reindeer who's an excellent decorator?

Deer-ator

Why did Santa's reindeer go to therapy at the North Pole?

They had a lot of 'deer-pressing' issues to work through.