inside every kind of area that people live in for long term, (houses,
apartments, townhomes,...) regardles of how the rooms are set up there
is usally at least one light on the celinging in every room except for
the living room, how come? why is that the only room that does not
have a built in light source?

HI,
I think this is so, because the living room is the one room in which
the furniture arrangement can significantly vary.  In the bedrooms,
dining room, etc., a central ceiling light fixture is usually
convenient.  In the livingroom  - with indirect lighting or whatever
people want, a central, ceiling light fixture is seldom desired, and
if not, then a cap for the wires is the last thing the housewife
wants.
That isn't very scientific, just a free comment.
Myoarin

that does seem like a verry probable reason.
allthough I still gotta wonder why they'd be so nit picky about having
caps on the celing of all places.

thanks for your help.

I think this is a matter of fashion, tradition and budget. Even in the
US, houses that were built before the seventies tended to have
overhead lights in bedrooms. Now they don't. It saves money not to
have wiring to ceiling lights. When people remodel homes they
frequently install track lights or in-ceiling lights to suit their
particular needs. In modern homes much more wiring is needed for all
the electrical equipment people have now that they didn't have in
earlier times. I've read that many times older office buildings are
demolished instead of rewired for modern needs because it would be too
expensive to retrofit buildings for today's heavy electrical use.

I don't know what are common practices in other countries.

Thank you, that does answer that question as well.
and I do live in the US so I don't really care about how they do it in
other countries.

well between the two of you I got the answer I was looking for thanks so much.