Off with the mask

A while ago I found someone on Twitter by pure accident. Someone I used to chat with a lot a few years back on Westlife's message boards. And when I say a lot, I DO mean a lot. It was a group of us chatting away most nights about this and that and we knew one another pretty well.
I remember I used to be slightly jealous of this one person because of their looks, their social life, their boyfriend, etc. So when I accidentally "bumped" into her on Twitter I was quite curious to find out how she is now, although she didn't seem too happy to be talking to someone "from back then". Or maybe she never really liked me back then either.
Anyway....I asked her if she was still at her job and if she was still with X.

She replied by saying she never worked "there" and she was never with someone called X.

Which lead me to thinking: what else did she lie about?! why do people feel the need to lie about their lives when talking to people online?!
I don't get it.
I have no problems in exposing my pretty lame, frustrating life and sharing most of my problems with the world. Why would I have to lie?! At the end of the day if I did lie, my life would still be what it is and wouldn't suddenly turn into my little fantasy.

I don't get it.....