Why can't I be manly?

I bought a few games on Steam last night, namely:
Left 4 Dead 2
Polynomial
VVVVVV
Audiosurf
Beat Hazard
Bit Trip Beat
Rhythm Zone

Because I'm on a Mac, I can't play Audiosurf, Beat Hazard, or Rhythm Zone, but that's not too bad because I really wanted Bit Trip and Polynomial and the pack of all 5 were like, £4. I then got L4D2 because it was £4 and VVVVVV because I heard it was good.
Bit Trip is fun, I like the music and I loved it on Wii.
Polynomial is the most beautiful game I've played and is a great chillout game when you need some brain break.
VVVVVV is OK, I never was a big retro gamer so I kind of don't get it. It's fun though.
Now Left 4 Dead...
This is where my issue is.
I am petrified of aliens and zombies. I can just about play the first few levels of Halo because they aren;t that bad.
I have now realised that I can never play Left 4 Dead because I cannot bring myself to go down the flights of stairs to kill zombies. It's a pathological fear, which sucks all the manliness out of my body. Most of my friends have completed it, including the girl ones.
It's just the panic of things coming to kill your face that I don't get. I get all panicky and screechy and OMGWHATWASTHAT. Whether it's zombies, aliens, zombie aliens or general nasty people, I just cannot be dealing with it.
Yet another pointless purchase, like Resident Evil, Halo Reach and Half Life that I'm too much of a pussy to play. Except I can't trade a Steam purchase in at Game for Microsoft Points to buy Rock Band DLC.
I'm such a pussy.