He's not sure why he lies. When there's an opportunity to embellish fact for effect, he does. Maybe he's shielding a narcissistic tendency to avoid appearing dumb or simple. People are amused by the extreme, the boisterous
and the implausible. He lies to exit or avoid an uncomfortable situation. Repeatedly disappointing others seems to absolve him from feeling guilty.

“Last night a homeless woman approached me with a conversation. Having trekked from New Hampshire and living under a bridge, she described her unsuccessful three day search for her brother. She was thin, articulate, with a dark complexion, wiry grey curls and dressed in plaid pajama pants and a dusty blue shirt. Anticipating that she may ask me for money, I rummaged through my
pocket inventory with no avail. Apologetically declining her appeal, I became self-conscious of my clothes, education, bicycle and the takeout food I was waiting for. She wouldn't look at me in the eyes after that.”

She may have been lying about her situation--her brother, the bridge, New Hampshire. Despite her sincerity, he had no reason to believe or not believe what she was describing. Even if she wasn't honest, he can admire lies that disguise self-survival as opposed to lies of gratification and selfishness.