"the line"

Liars are thrust to hell...
however,
is it possible for a person not to lie?
does everyone know everything about you?
is omitting truths also lying?
for example, yes, those jeans make you look fat
lawyers often lie to prove cases
corruption... the government lies to the public all the time
false advertising
its everywhere. lying is part of life.
im just a little bit... baffled as to if lies are EVER okay?
like on the show "lie to me"
thats where this kinda started
would you lie to someone or keep something from them if you knew it was going to save your life?
or if made them do their job better which is necessary.
would you lie to protect your family from going to prison?
would you lie and tell the detective their boyfriend was okay (when reality they were in the hospitol) so they could concentrate and finish the case?
if you started developing feelings for your boss and you knew he was into you too, would you "lie" to yourselves and each other to keep it professional AND more importantly, to stay loyal to your spouce EVEN if your spouse was a recovering cocaine addict with whom you have problems with daily?
Ethics ethics ethics. maybe i need to take that class. or read some articles:
http://www.bbc.co.uk/ethics/lying/
http://www.scu.edu/ethics/publications/iie/v6n1/lying.html
http://olinethicist.blogspot.com/2006/03/is-lying-wrong.html
http://www.nytimes.com/1997/07/02/us/the-ethics-of-lying.html

ill maybe do a follow up after i do some reading myself
but i will finish with that idea.
they said there was a line where investigators have to decide when to cross it...
where they know what the other person doesnt want them to know
and they have to decide whether or not to exploit it or even bring it up.
when you know the other person is lying, or you know there is something there.
the elephant in the room if you will...
do you acknowledge it?
im kinda in this situation right now. *shrug*
figure it out with time i guess.