Oh, what a tangled web we weave, When first we practice to deceive!!

The fundamental reason why people lie is because it mostly works

Does it? Hell yes...I like the link link above and the little description of why we lie.

Consider this scenario..

'Babe, does this dress make me look fat?'
'No Hun, you look great! Actually you look damn sexy ...'

Hmmm...

or the truthful answer...

'No, hun, the dress doesn't make you look fat. The fat clingling on your hips makes you look fat. I thought you had to cut down on the calories rather than just 'count' them, and your fatter than when we first met...you could just wear the other dress that fits you'

Now here is a good example as to why lying benefits both the liar and the gullible.
She feels great, and happy with herself. He is still alive and well, and his chances of getting laid later on have dramatically increased...

Its simple really, we all lie, and all things considered, we probably like and benefit from being lied to in some situations.

It sounds an outrageous suggestion, but if we constantly heard about it every time someone didn't like what we say, told us how they really feel, how THAT dress was a complete abomination, and that hair cut was a butcher job, we probably wouldn't leave the house through low self-esteem and motivation, and probably a lack of friends. We rely on compliments and support from friends and family, and when we are given the alternative 'reality check', we often don't like it!

And as for lying to others, well we all do it! Its fundamental to maintain any relationship! And I don't mean the great dirty, deceptive lies. Its the compliments that you don't whole-heartedly mean, it's the little negative comments that you ignore and replace with complimentary niceties.