Personally, I find excessive lights on rigs gaudy/tacky; about as bad as scrawling "JESUS" or crosses or "John 3:16" in the dirt of the back of a trailer.
So I have a few possible theories on reasons for this excessive lighting phenomena:
(A) Owner has OSD (obsessive-compulsive disorder).
(B) It is simply a case of "monkey see, monkey do".
(C) Owner is an exhibitionist (i.e. "look at me!").
(D) Owner is too skeer'd to drive at night without them.
Anybody else got any other theories? Or which one(s) of the above do you think is the most common reason? I am simply curious. The folly of man truly amazes me at times!