enough of definitions

I have spent so much time trying to find out the definition of truth and more i dig deep i find that everyone has their on version of truth, the one that suits their needs and doesn't really clash with their ideologies, and yet i find myself short of people who actually speak the truth. everyone wants to deal with the person who speaks truth while they themselves lie. My point here is that its the complex definitions that matter, but the people who actually speak truth, no matter the circumstances.

                  For example since childhood till today, i have studied in different institutions and no where my teacher advise their students to be truthful. Every institution cares about the result from their students and no institute tries to tell their student that "be truthful", because lets face it, out there in the world, the common perception is that truth can cause problems for you and that is true to some extent. 

                 Every single field, from government job to private business, everyone bends the truth according to their needs. Take cigarette for example or alcohol for that matter, everyone knows that these things are bad for health and yet they are advertised in such a way that everybody buys them and uses them. i mean they can be honest in their advertisements and say that these products are extremely harmful but no, all they do is glamorize the product and in the end show a small written text "smoking is injurious to health" and that's it. you know why they do it? because its easier to lie and get the benefits out of something then telling the truth and loose all their money.