Who am I

Who am I?
Most of you will never see me.
I give you gifts on a certain day.
My favourite color is red.
I will only come if you've be good.
The only food I ever eat is sweats.
Who am I?

Who am I?
I make loud sounds but people think its not me.
Im used mostly when there is a screen.
The sounds I make can vary.
I have no feelings but I can make people feel them.
My size can vary it depends on your money.
Who am I?