Why we lie

People lie all the time, and only sometimes is it to conceal misbehavior.  I lie when telling the truth will do no good and may harm or hurt someone, and I lie when it is to my benefit to lie in situations where the asker has no right to the truth but my refusing to answer will be taken badly.

People also lie to "one-up" someone -- the bigger fish business.  On message boards it is often just to get attention.

Indeed, your "not wanting to tell your experience" strikes me as of that species.

There is also a huge phenomenon not much recognized of pious fraud.  This is where convincing another of what you believe is more important than honesty.

I practice a tripartite ethics -- mindful compassion, helpfulness, and not using people as a means to an end.  This is different from our cultural ethics we call conscience, which says all lies are wrong.  What I say is we have to balance compassion with being helpful with never using someone for our own ends.  Sometimes the balance is difficult to see, and sometimes we make mistakes, but that applies to all ethical systems.  We have to be rational about it.