I'm the great pretender?

I asked a friend for some feed back about me and he said
"sometimes i feel tat u are pretending"

It struck me that I've pretend a lot and yes, I admit it.
Pretending to know what I'm doing or talking about, but in fact I don't even have a clue, why am I pretending on such things? To impress people? To make myself look good? Aah... fuck, bloody waste of time.
When I'm unhappy about something, I will pretend that nothing has happened or pretend that I'm OK with it, I keep everything to myself so that others can be happy or what so ever.
Pretending to be happy is the saddest thing to do, try being happy when someone you cared for says "You are not important." try to fake your expression will automatically put a big neon sign telling the world that you are being plastic. Personally I've experience it myself, I mean, try to pretend you are being nice to someone but in reality that person hates you. It really annoys me a lot to have somebody pretending to be nice to me and it made me realized that how the people whole I pretend to like really felt.
Why on earth am I doing such nonsense on to myself? Kinda pissed at myself when I come to think about it. What a major fuck up thing to do, great pretender my ass!