Why - because I said so, that's why.

Admiring the Christmas trees displayed in his neighbours windows, a child asks his father,
"Daddy can we have a Hanukkah tree?"
"What. No of course not." says his father.
"Why not?" asks the child.
Bewildered, his father replies,
"Because the last time we had dealings with a lighted bush we spent 40 years in the wilderness."