Because you haven't put enough effort into your Christmas lights until your family is in danger.
What is it about Christmas tree ornaments that sends cats into destruction mode? It's like they all have big signs on them that say "annihilate me!"
From the submitter:
(actually a trick - the hole in the ceiling is actually a box that is supported by the top of the tree which was cut flat)
Dammit. You had me going there...