Why Men Lie?

Have you ever got sick of men lying to you? When they look straight into your eyes and lie to you? Honestly speaking, i'm sick of it. I do not know when to trust them, when not to. Hence, i went online, to look for reasons why they would lie. So, here are a few:

1. For SEX - yes, they'll do anything for sex.
   
2. It's in their blood - they love lying - and they don't believe they're really "lying" if they withhold some of the truth.
3. To avoid conflict
4. When they wanna avoid something imposed on them
5. He's not confident of himself
6. To get out from a mess
7. When they are busted
8. When they think their girlfriend / wife is stupid
9. For other monetary / status gain

I still don't get it.If a man treats you as his good friend, why would he still lie to you? Hmm.. Man.. justify this~~!!