Ever since beating Halo Reach on Legendary, and earning that BEAT REACH SOLO LEGENDARY achievement. I said "might as well try my hand at all of them."
So I did, and The Flood made me pay for it, not a big problem in Halo 3 (except for that one shitty as designed level where you finally get Cortana), or in Halo 2...but in Halo: CE, that's when I was nearly in tears.
But I was victorious. And it was only because I had a shotgun, and managed to get the an invisibility cloak. The entire time I was running and gunning my way out of there, sometimes lost because i had no idea where I was going.