IVIV ARPAnet - "science-fictional Christmas tree" (53)

[Doug Millison]

Another laugh-out-loud moment for me, on p 53:

"Arpanet,"Fritz announced.
"Ah, no I'd better not, I've got to drive and stuff, maybe just give  
me one for later--"
"It's a network of computers, Doc, all connected by phone lines."

Fritz thus instructs Doc that the ARPAnet is not a drug or pill that  
he can take away and swallow later.
Although, given the "drug" that the internets have become for some,  
maybe the experience is similar to being on dope.

I wonder why a "Christmas tree" and not a comparison to some other  
object?